GB2424548A

GB2424548A - Mobile Video Telephony Method.

Info

Publication number: GB2424548A
Application number: GB0519801A
Authority: GB
Inventors: Po Ken Siu
Original assignee: Hutchison Whampoa Enterprises Ltd
Current assignee: Hutchison Whampoa Enterprises Ltd
Priority date: 2005-03-22
Filing date: 2005-09-29
Publication date: 2006-09-27
Anticipated expiration: 2025-09-29
Also published as: GB0519801D0; TWI384896B; CN1838825B; HK1081069A2; CN1838825A; TW200635395A; GB2424548B

Abstract

A method of providing mobile video telephony service in a 3G mobile phone network to an inbound roaming mobile phone user from a 2G mobile phone network, comprises steps: <SL> <LI>(a) providing a system server (10) connected to the 3G and 2G networks; <LI>(b) obtaining by the server (10) the location of the user in the 3G network; <LI>(c) obtaining by the server (10) from a home location register (30) of the 2G network a subscriber profile with a features list including a 2G mobile phone number of the user; <LI>(d) revising by the server (10) the features list of the subscriber profile by activating video telephony service and replacing the 2G mobile phone number with a 3G local mobile phone number; and <LI>(e) updating by the server (10) the revised subscriber profile of the user at a mobile switching center (20) of the 3G network, thereby enabling the user to make an outgoing video call in the 3G network. </SL>

Description

MOBILE VIDEO TELEPHONY METHOD The present invention relates to a method for use in a Third Generation (3G) mobile phone network offering mobile video telephony services for inbound Second Generation (2G) roaming subscribers.

BACKGROUND OF THE INVENTION Video telephony service is a new service in the 3G mobile telecommunication that allows a 3G mobile customer to send or receive a video call to or from another 3G mobile terminal or a fixed line video terminal. in order to enjoy this service, the 3G customer should use a 3G terminal that is equipped with video telephony capability. In addition, such video telephony service should be subscribed and defined in a subscriber profile as a video service parameter. For a WCDMA (Wideband Code Division Multiple Access) network, such a video service parameter is defined as in 3GPP TS 22.002. The video telephony (known as CS multimedia telephony in the art) is a bearer service that utilizes the service parameter, known as Synchronous Transparent Data Service (BS30). The 3G network is evolved from the 2G network, and it allows a 3G mobile user with a 2G compatible handset to automatically roam into the 2G network to also enjoy the 2G compatible service, such as voice service and Short Message Service (SMS). Vice versa, a 2G mobile user can also roam into the 3G network, if the roaming connection between the 2G and 3G networks are established and the 2G mobile user is using a 3G compatible terminal. However, as video telephony service is not supported by the 2G network, the relevant service parameter to support video telephony service is not normally defined in the 2G network. As a result, a 2G inbound roaming customer cannot update this video service parameter (Synchronous Transparent Date Service BS30) in the 3G network during roaming to enjoy video telephony service. The subject invention seeks to mitigate or at least alleviate such a shortcoming by providing a 3G video telephony method.

SUMMARY OF THE INVENTION According to the invention, there is provided a method of providing mobile video telephony service in a Third Generation (3G) mobile phone network to an inbound roaming mobile phone user from a Second Generation (2G) mobile phone network, comprising the following steps: (a) providing a system server connected to the 3G and 2G networks; (b) obtaining by the system server the location of the user in the 3G network; (c) obtaining by the system server from a home location register of the 2G network a subscriber profile with a features list including a 2G mobile phone number of the user;(d) revising by the system server the features list of the subscriber profile by activating video telephony service and replacing the 2G mobile phone number with a 3G local mobile phone number; and (e) updating by the system server the revised subscriber profile of the user at a mobile switching center of the 3G network, thereby enabling the user to make an outgoing video call in the 3G network. Preferably, step (b) comprises determining by the mobile switching center the location of the user in the 3G network and then updating the said user location at the system server. More preferably, step (b) includes subsequently verifying by the system server the identity of the user based on International Mobile Subscriber Identity (IMSI) associated therewith. More preferably, step (b) includes subsequently updating by the system server the said user location at the home location register. It is preferred that step (d) includes activating video telephony service by adding a service parameter therefor in the features list of the subscriber profile. It is further preferred that the service parameter in step (d) is inserted to or checked from a Mobile Access Protocol (MAP) message 'Insert Subscriber Data' sent from the system server to the mobile switching center. Preferably, step (b) to step (e) are performed during roaming of the user into the 3G network. In a preferred embodiment, the mobile video telephony method includes the following steps: (f) sending by the system server an enquiry for the said user location from the home location register, upon a video call made to the user; and (g) providing by the home location register the said user location to the system server, based on which the system server can obtain a roaming number of the user for delivery of said video call. More preferably, the enquiry in step (f) comprises a request for send routing information for short message service based on the 2G mobile phone number. More preferably, the said user location comprises an address at the mobile switching center. Further more preferably, the enquiry in step (f) for retrieving the address from the home location register comprises: obtaining from the system server an International Mobile Subscriber Identity (IMSI) for the user and the 2G mobile phone number based on the called number of said video call; and sending to the home location register a Mobile Access Protocol (MAP) message 'Send Routing Information for Short Message'. Specifically, the system server comprises a signalling server for relaying roaming signalling messages, an application server for collecting relevant information from the roaming signalling messages, running application logics for signalling parameters manipulation, imitating signalling messages to the 2G network for call routing information, and co-operating with the 3G network for video incoming call routing, and a database server for storing information for the 2G network. More specifically the signalling server supports SS7 Mobile Access Protocol (MAP) stacks (3GPP TS29.002 compliant) for decoding the signalling messages. It is preferred that the 3G local mobile phone number in step (d) is dedicated to a particular international Mobile Subscriber Identity (IMSI) range of the 2G network. It is preferred that the 3G local mobile phone number in step (d) replaces the 2G mobile phone number field in a Mobile Access Protocol (MAP) message `Insert Subscriber Data' that updates the revised subscriber profile in step (e) .

BRIEF DESCRIPTION OF DRAWINGS The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic signal flow diagram illustrating initial procedures of an embodiment of a mobile video telephony method in accordance with the invention; and Figure 2 is a similar schematic signal flow diagram that illustrates later procedures of the mobile video telephony method of Figure 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, there is illustrated a mobile video telephony method embodying the invention for providing 3G video telephony service to a 2G mobile handset user from a 2G GSM (Global System for Mobile Communications) mobile phone network of a home location in a 3G WCDMA mobile phone network of a visiting location. The method may be employed by a 3G mobile phone service provider who operates via a set of system servers 10 connected in the general telephone network. The system servers 10 include a number of signalling servers connected between the 3G WCDMA network and one or more of its roaming partner, i.e. the 2G GSM network, generally for relaying roaming signalling messages to enable international roaming services. At least some of these signalling servers support SS7 MAP protocol (Mobile Access Protocol) stacks (3GPP TS29.002 compliant) for processing or encoding/decoding the signalling messages. Also included are application servers for, inter alia, collecting relevant information from the roaming signalling messages, running the application logics for signalling parameters manipulation, imitating signalling messages to the GSM networks for call routing information, and co-operating with the WCDMA network for video incoming call routing. There are also database servers for storing information for the individual 2G GSM networks, including particulars of the users who have subscribed to the roaming and video telephony services. In the 3G network there is a Mobile Switching Center or MSC 20 for switching control, which includes a Visiting Location Register or VLR 21 for holding updated particulars of roaming users e.g. their locations, as is generally known in the art. The 2G network includes a home location register or HLR 30 that contains generally the same particulars of the users as is also known in the art. Figure 1 illustrates the initial roaming procedures of the subject mobile video telephony method in steps 1 to 5. Upon a 2G roaming subscriber turning on the power of his 3G compatible handset (step 1), the 3G MSC 20 will detect the user's new location and then send an updated location (address) message to inform the relevant system server 10 that this 2G subscriber intends to roam into the 3G network (step 2). The system server 10 will verify the identity of the roaming subscriber based the IMSI (International Mobile Subscriber Identity) associated with him, to ensure that he is a subscribed user and will then pass on his updated, current address (at the VLR 21) to inform the 2G HLR 30 to which the user belongs (step 3). In response, the 2G HLR 30 will check the user's roaming profile and then send a MAP message 'Insert Subscriber Data' to the system server 10, thereby inserting the user's subscriber profile with features list, including his 2G mobile number and an indication that no video telephony service is available (step 4). Upon receipt of the subscriber profile, the system server 10 will verify the identity of the 2G inbound roaming subscriber again. if the subscriber does not have video telephony service and the visiting MSC (VMSC) 20 is associated with a 3G network, the system server 10 will add video telephony service into the user's features list and replace the user's 2G mobile number with a local 3G mobile number (step 5). The video telephony service for WCDMA networks is added or activated by defining a BS30 parameter in accordance with 3GPP TS 22.002. This BS30 parameter is inserted to or checked from the MAP message 'Insert Subscriber Data' sent from the system server 10 to the MSC 20. The local 3G mobile number replaces the original 2G mobile number field in the MAP message `Insert Subscriber Data' to the MSC 20. This 3G number is assigned to the Cam inbound roaming subscriber on a subscription basis and is dedicated to a particular IMSI range of the 2G mobile network. The revised subscriber profile with features list including the 3G mobile number will then be inserted by way of another MAP message 'Insert Subscriber Data' sent to and updated at the MSC 20, so that the user can make an outgoing video call. As a result of the aforesaid process, and in particular by inserting video telephone service and replacing the 2G mobile number with a local 3G mobile number upon roaming into the 3G network, the 2G inbound roaming subscriber is now able to make an outgoing video call to another 3G user in that network. At this stage, since video telephony is not supported in the 2G network, an incoming video call made to the roaming 2G subscriber will fail. The subject video telephony method solves this problem by way of an enquiry for the 3G roaming number to receive the incoming video call, said enquiry being made to the HLR 30 by way of SMS (Short Message Service. Figure 2 illustrates the later procedures of the subject mobile video telephony method in steps 6 to 13. In the visiting location, there is a Gateway Mobile Switching Centre or GMSC 40 for initially receiving or terminating an incoming video call for the roaming 2G subscriber made to the aforesaid local 3G number (step 6). The GMSC 40 will subsequently send to the system server 10 an enquiry for the 2G HLR 30 for making the video call with the local 3G number (step 7). The enquiry comprises a MAP signalling message 'Send Routing Information' to obtain the user's current location. In response, the system server 10 will first check mapping of the local 3G number and translate this number into the 2G mobile number of the roaming user. This process involves looking up or retrieving from the relevant database server 10 of the IMSI (International Mobile Subscriber Identity) for the user and his mobile number in the 2G home network based on the called number of the incoming video call. The system server 10 will then send the enquiry to the 2G HLR 30 as a MAP message requesting 'Send Routing Information for Short Message' based on the 2G mobile number using the SMS (Short Message Service) algorithm, with priority bit set to `high' (step 8). The 2G HLR 30 will answer to the system server 10 with the current visiting MSC address of the user i.e. his current location (step 9), as previously determined by the VMSC 20 and updated at the HLR 30 (step 2). Upon retrieving the user's current VMSC address, the system server 10 will check this VMSC address to see whether or not mobile incoming video call service is allowed in the Public Land Mobile Network (PLMN) according to the data stored in the relevant database server. If incoming video call service is available, the system server 10 will send a MAP message 'Provide Roaming Number' including the bearer information (BS30) of video call type to the VMSC 20, retrieving therefrom the 3G roaming number of the user for forwarding the video call (step 10). If incoming video call service is not available, the call will be rejected by returning error in response to the MAP message 'Send Routing Information' to the GMSC 40 of the WCDMA network, with cause code `Facility is not supported in the PLMN'. The VMSC 20 will reply to the system server 10 with the roaming number as requested (step 11). The system server 10 will then provide the roaming number to the GMSC 40 of the WCDMA network (step 12), which will in turn call the inbound 2G roaming customer with the 3G roaming number to deliver the video call to him (step 13). Thus, in order to allow a 2G inbound roaming customer to enjoy video telephony service in a 3G mobile network, a BS30 service parameter is first added to the features list of the subscriber profile during roaming into the 3G network. By inserting the BS30 parameter and replacing the mobile number of this 2G inbound roaming subscriber with a 3G local mobile number, the 2G inbound roaming customer is then able make, and receive, a video call. The invention has been given by way of example only, and various modifications of and/or alterations to the described embodiment may be made by persons skilled in the art without departing from the scope of the invention as specified in the appended claims.

Claims

1. A method of providing mobile video telephony service in a Third Generation (3G) mobile phone network to an inbound roaming mobile phone user from a Second Generation (2G) mobile phone network, comprising the following steps: (a) providing a system server connected to the 3G and 2G networks; (b) obtaining by the system server the location of the user in the 3G network; (c) obtaining by the system server from a home location register of the 2G network a subscriber profile with a features list including a 2G mobile phone number of the user; (d) revising by the system server the features list of the subscriber profile by activating video telephony service and replacing the 2G mobile phone number with a 3G local mobile phone number; and (e) updating by the system server the revised subscriber profile of the user at a mobile switching center of the 3G network, thereby enabling the user to make an outgoing video call in the 3G network.

2. The mobile video telephony method as claimed in claim 1, wherein step (b) comprises determining by the mobile switching center the location of the user in the 3G network and then updating the said user location at the system server.

3. The mobile video telephony method as claimed in claim 2, wherein step (b) includes subsequently verifying by the system server the identity of the user based on International Mobile Subscriber Identity (IMSI) associated therewith.

4. The mobile video telephony method as claimed in claim 2 or claim 3, wherein step (b) includes subsequently updating by the system server the said user location at the home location register.

5. The mobile video telephony method as claimed in any one of claims 1 to 4, wherein step (d) includes activating video telephony service by adding a service parameter therefor in the features list of the subscriber profile.

6. The mobile video telephony method as claimed in claim 5, wherein the service parameter in step (d) is inserted to or checked from a Mobile Access Protocol (MAP) message ',Insert Subscriber Data' sent from the system server to the mobile switching center.

7. The mobile video telephony method as claimed in any one of claims 1 to 6, wherein step (b) to step (e) are performed during roaming of the user into the 3G network.

8. The mobile video telephony method as claimed in any one of claims 1 to 7, including the following steps: (f) sending by the system server an enquiry for the said user location from the home location register, upon a video call made to the user; and (g) providing by the home location register the said user location to the system server, based on which the system server can obtain a roaming number of the user for delivery of said video call.

9. The mobile video telephony method as claimed in claim 8, wherein the enquiry in step (f) comprises a request for send routing information for short message service based on the 2G mobile phone number.

10. The mobile video telephony method as claimed in claim 8 or claim 9, wherein the said user location comprises an address at the mobile switching center.

11. The mobile video telephony method as claimed in claim 10, wherein the enquiry in step (f) for retrieving the address from the home location register comprises: obtaining from the system server an International Mobile Subscriber Identity (IMSI) for the user and the 2G mobile phone number based on the called number of said video call; and sending to the home location register a Mobile Access Protocol (MAP) message 'Send Routing Information for Short Message'.

12. The mobile video telephony method as claimed in any one of claims 1 to 11, wherein the system server comprises a signalling server for relaying roaming signalling messages, an application server for collecting relevant information from the roaming signalling messages, running application logics for signalling parameters manipulation, imitating signalling messages to the 2G network for call routing information, and co-operating with the 3G network for video incoming call routing, and a database server for storing information for the 2G network.

13. The mobile video telephony method as claimed in claim 12, wherein the signalling server supports SS7 Mobile Access Protocol (MAP) stacks (3GPP TS29.002 compliant) for decoding the signalling messages.

14. The mobile video telephony method as claimed in any one of claims 1 to 13, wherein the 3G local mobile phone number in step (d) is dedicated to a particular International Mobile Subscriber Identity (IMSI) range of the 2G network.

15. The mobile video telephony method as claimed in any one of claims 1 to 14, wherein the 3G local mobile phone number in step (d) replaces the 2G mobile phone number field in a Mobile Access Protocol (MAP) message 'Insert Subscriber Data' that updates the revised subscriber profile in step (e).

16. A method of providing mobile video telephony service in a Third Generation (3G) mobile phone network to an inbound roaming mobile phone user from a Second Generation (2G) mobile phone network, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.