WO2012080781A1

WO2012080781A1 - A method and system for detecting mobile numbers used by international gateway bypass (sim box) operators

Info

Publication number: WO2012080781A1
Application number: PCT/IB2010/055762
Authority: WO
Inventors: Gayan Samarasekara; Jagath Premawardana
Original assignee: Gayan Samarasekara; Jagath Premawardana
Priority date: 2010-12-12
Filing date: 2010-12-12
Publication date: 2012-06-21

Abstract

A method and system to track down the MSISDNs used by International Gateway Bypass (SIM Box) operators. In one embodiment, an IDD bypass detection server is connected to the wireless mobile network that uses MAP protocol. This server is provided with a set of IMSIs of Roaming test SIMs from the existing roaming partners of the aforementioned network operator, for each of which the IDD bypass detection server will generate location update request towards the respective HLR. (In this case, the IDD bypass detection server essentially assumes the function of a virtual VLR.) After receiving the subscriber data for each IMSI, the server then starts initiating calls towards each of the roaming numbers, by utilizing any protocol capable of generating a call. (eg. ISUP/BICC/SIP etc). When each call is reached the FPLMN, their HLR will request an MSRN from the IDD bypass detection system, which is acting as the virtual VLR. Upon receiving the PRN, the IDD bypass detection system issues a special, perhaps "disguised" MSRN to the FPLMN HLR, thereby call will be routed to the IDD bypass detection system either as a direct call using a protocol such as ISUP/BICC/SIP or as an IDP via CAMEL protocol, with the calling and called party information. (Note: - To use CAMEL, the "disguised" MSRN number issued, should have been created in the HLR with TCSI configured towards the IDD bypass detection system, which assumes the SCF function as well in this case). The call, reached the IDD bypass detection system can be released with an appropriate release cause so that there won't be any chargeable CDR at any location. By analyzing the calling party (CLI) information of the received call, the system can check whether it is a call originated from a SIM box or not.

Description

Title of Invention: A METHOD AND SYSTEM FOR DETECTING

MOBILE NUMBERS USED BY INTERNATIONAL GATEWAY

BYPASS (SIM BOX) OPERATORS

Technical Field

[1] Embodiments of the present invention relate generally to wireless communication technology and, more particularly, relate to methods and systems for the identification of the mobile numbers used by International Gateway Bypass (SIM Box) Operators. Background Art

[2] GSM Service providers today face an immense problem of losing their potential revenue from International voice carriers which are directly connected to the operator, with the expansion of International Gateway Bypass operators. There are a number of terms used to refer to them including, IDD Bypass Operators, SIM Box Operators and Grey IDD Operators. Due to IDD Bypass mechanism, voice quality degrades considerably and CLI (Caller line Identification) never appears correctly.

[3] Figure 1 shows a normal International Direct Dial (IDD) call. A subscriber in

PLMN-B calls a subscriber in PLMN-A. The call should come via an International voice carrier and be terminated at PLMN-A.

[4] Figure 2 shows the basic mechanism behind the IDD Bypass Operation. A subscriber in PLMN-B calls a subscriber in PLMN-A. PLMN-B sends the call via Internet to a SIM Box operator. The SIM box operator re-originates the call as a local call, using one of his SIM cards. The receiver of the call will see the CLI of the local SIM used by the SIM Box operator, instead of the real CLI.

[5] One prior art solution is seeking the help of a third party who terminates calls on a given list of numbers located in the PLMN-A and help the PLMN-A operator to identify the Mobile Subscriber Integrated Services Digital Network Numbers

(MSISDN or simply the telephone number) used by IDD Bypass operators and black list them. This process costs operators a lot and totally depends on a third party company. In addition the operators have to schedule this process time to time.

Description Of Drawings

[6] Figure 1 shows a simplified version of a normal International Direct Dial (IDD) call scenario for a call made from a Mobile Station (MS) in PLMN-B to a Mobile Station in PLMN-A.

1. MS(B) dials the number of MS(A). The call reaches the Mobile Switching Center (MSC) of PLMN-B

2. PLMN-B analyses the number and sends it to an International Voice Carrier 3. International Voice Carrier analyses the number and sends it to PLMN-A

4. PLMN-A terminates the call to MS(A)

[7] Figure 2 shows a simplified IDD call from MS(B) to MS (A) coming through a SIM

Box operator.

1. MS(B) dials the number of MS(A). The call reaches the MSC of PLMN-B

2. PLMN-B analyses the number and sends it to an International Voice Carrier

3. International Voice Carrier sends the call to a SIM Box operator via Internet or any other data network.

4. The SIM Box operator re-originates the call with one of the SIM cards he possesses.

5. PLMN-A terminates the call to MS(A)

[8] Figure 3 shows a detailed message flow of one embodiment of the present invention.

(MS(B) represents the roaming SIM, from PLMN-B, already location updated in IBD server.)

1. IBD server initiates a call to the mobile number of MS(B) with a known CLI.

2. GMSC(A) sends the call to an International Voice Carrier.

3. The International Voice Carrier sends the call to the GMSC(B) of PLMN-B.

4. GMSC(B) sends Send Routing Info (SRI) message to the HLR(B)

5. HLR(B) checks the current location of MS(B). Since it is location updated in the IBD server in PLMN-A, the HLR(B) sends a Provide Roaming Request message towards the IBD server, via an International SCCP carrier.

6. PRN request comes to IBD server.

7. IBD server assigns an MSRN number. This MSRN number is also defined in HLR(A) with CAMEL TCSI enabled towards IBD server. A PRN Ac- knowlegement message is sent back via the International SCCP carrier.

8. PRN Acknowlegement message reaches the HLR(B)

9. HLR(B) sends the SRI Acknowledgement towards GMSC(B) with the MSRN number.

10. GMSC(B) re-initiates the call towards the MSRN number via International Voice Carrier.

11. International Voice Carrier sends the call to a SIM Box operator

12. SIM Box operator Genrates a new call using one of his SIM cards.

13. The call receives the GMSC(A)

14. GMSC(A) sends SRI request for the called number (The MSRN issued at step 7)

15. HLR(A) recognises the CAMEL TCSI in the profile of the number and sends the SRI Acknowledgement with CAMEL routing information. 16. GMSC(A) sends the Initial Detection Point message to IBD Server

17. IBD server processes the information and sends a release call request to the GMSC(A) to end the call.

Brief Description

[9] The present invention describes a method and a system which can be deployed to detect the MSISDNs of the SIMs which are used by IDD bypass operators by the operator himself, without the involvement of any third party company.

[10] The present invention utilizes "roaming test SIMS". Almost all the GSM operators have roaming agreements with most of the countries in the world, directly or via a roaming HUB, today. This means a GSM operator (PLMN-A) possesses roaming test SIMs from their roaming partners that can perform successful "Location updates" in PLMN-A.

[11] Basic idea is to; bring down terminating calls from all over the world into the

PLMN-A operator who wants to detect those MSISDNs used by IDD Bypass operators. Bringing an IDD call from abroad can be simply achieved by making a call from any PLMN-A number to the roaming SIM. Since the roaming test SIM is latched to PLMN-A, the call will ultimately terminate back to the PLMN-A network, but via an international voice path.

[12] Specifically, an MSRN that belongs to PLMN-A will be dialed by roaming SIM's PLMN-B to make the MTC call successful on the roaming test SIM. If the Call reaching roaming test SIM is with a Local CLI then it is obviously coming via an IDD Bypass operator. Then by black listing such MSISDNs appeared as the CLI, PLMN-A operator can resist IDD Bypass operators. If this process continues, IDD Bypass operators will have no choice but to terminate their operations.

[13] Assuming that these IDD Bypass operators become intelligent enough to not dial MSRN levels of any operator and dial only MSISDNs of valid ranges, IDD Bypass Detection system extends the solution to have MSRNs which are real MSISDNs in PLMN-A network.

Detailed Description

[14] The present invention describes a method and a system which can be deployed to detect the MSISDNs of the SIMs which are used by IDD bypass operators by the operator himself, without the involvement of any third party company.

[15] The description of the present invention gets involved with two public land mobile networks (PLMN). The first, PLMN-A is the one in which the present invention is implemented. The second, PLMN-B is an arbritary foreign PLMN, with which PLMN-A has a roaming agreement and is suspected to be sending calls to PLMN-A via SIM Box operators. [16] The IDD Bypass Detection Server (IBD Server) is connected to PLMN-A and utilizes Mobile Application Part (MAP) protocol, and optionally Customized Application of Mobile Enhanced Logic (CAMEL) protocol. In addition, it is capable of handling at least one protocol capable of originating calls, supported by PLMN-A, including but not limited to ISDN user part (IS UP), Bearer Independent Call Control (BICC) or Session Initiation Protocol (SIP).

[17] The present invention utilizes "roaming SIMS" from PLMN-B, which are in

possession of PLMN-A. As the first step, the IBD Server initiates location updates for the "roaming SIMS" of PLMN-B, acting as a Visitor Location Register (VLR). After this was successful, the IBD Server then initiates calls towards each of the SIMs that were location updated, with a known CLI.

[ 18] Since all PLMN-B SIMs carry foreign MSISDNs, each call will reach the PLMN-B.

Then the Home Location Register (HLR) of PLMN-B will send the Provide Roaming Number (PRN) request, to the IBD Server back in PLMN-A.

[19] Upon receiving the PRN, the IBD Server assigns a Mobile Subscriber Roaming

Number (MSRN) for call termination and sends that detail back to the HLR of the PLMN-B. The assignment of the MSRN is a very critical part of the present invention. Normally, each mobile operator has a specific number range, reserved for MSRNs, which in many cases are easily identifiable. Therefore in some embodiments, the present invention uses MSRNs which are not in the normal MSRN range of the PLMN-A, instead in the range of normal MSISDNs of PLMN-A.

[20] PLMN-B dials the MSRN, and the call receives PLMN-A. PLMN-A has configured the network, so that the call receiving on the MSRN routes back towards the IBD Server. IBD Server then analyses the Caller Line Identification (CLI) information in the received call. If the CLI is idenfied to be a local mobile number (other than the original CLI), the call has come through a SIM Box operator.

[21] In some embodiments, the MSRN number assigned by the IBD Server is not a real MSRN, instead a number defined in the HLR which has Termination CAMEL Service Indicator (T-CSI) enabled towards the IBD Server. In that case when the call is received at the PLMN-A, the Gateway Mobile Switching Center (GMSC) sends a Send Routing Information message to the HLR since it lies in the range of MSISDNs. Then he HLR provides the GMSC with the T-CSI information. Thereby the GMSC will send CAMEL Initial Detection Point trigger towards the IBD Server. IBD Server then analyses the Caller Line Identification (CLI) information in the Initial Detection Point message. If the CLI is idenfied to be a local mobile number (other than the original CLI), the call has come through a SIM Box operator.

[22] In some embodiments , the MSRN number assigned by the IBD Server is not a real MSRN, instead a number defined in the HLR which has a call forwarding enabled towards another number. This second number is routed towards the IBD Server. In that case when the call is received at PLMN-A, the GMSC forwards the call to the second number, and the call is received at the IBD Server. IBD Server then analyses the Caller Line Identification (CLI) information in the received call. If the CLI is identified to be a local mobile number (other than the original CLI), the call has come through a SIM Box operator.

[23] In some embodiments , the MSRN number assigned by the IBD Server is not a real MSRN, instead a number defined in the HLR which has a call forwarding enabled towards another number and has Origination CAMEL Service Indicator (O-CSI) enabled towards the IBD Server. In that case when the call is received at the PLMN-A, the Gateway Mobile Switching Center (GMSC) sends CAMEL Initial Detection Point trigger towards IBD Server. IBD Server then analyses the Caller Line Identification (CLI) information in the Initial Detection Point message. If the CLI is identified to be a local mobile number (other than the original CLI), the call has come through a SIM Box operator.

[24] After receiving the call details, the IBD Server has the option of releasing the call of with a cause code of choice.

[25] Although the present invention has been described with reference to specific

exemplary embodiments, it will be recognized that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense.

Claims

A method of detecting the MSISDNs used by International Gateway Bypass (SIM Box) operators, the method comprising : location updating any number of roaming SIMs in a VLR; generating calls to the MSISDNs of the roaming SIMs location updated in the aforementioned VLR; issuing MSRNs for the each PRN (provide roaming number) request received as a result of generating of the calls;

capturing identification information associated with the calling party of the calls received for the roaming SIMs location updated in the aforementioned VLR.

The method of claim 1, wherein the MSRNs issued are not in a real MSRN range, instead in the range of normal MSISDNs of the mobile network (PLMN-A).

The method of claim 2, wherein the MSRNs issued are not in a contiguous range, but scattered arbitrarily in the number pool of the mobile network (PLMN-A).

The method of any of the claims 1 - 3, wherein each number used as an MSRN is defined in the HLR with CAMEL TCSI enabled towards a CAMEL capable entity, which uses the information in the CAMEL TCSI trigger to capture the identification information.

The method of any of the claims 1 - 3, wherein each number used as an MSRN is defined in the HLR with call forwarding activated towards any number and CAMEL OCSI enabled towards a CAMEL capable entity, which uses the information in the CAMEL OCSI trigger to capture the identification information.

The method of any of the claims 1 - 3, wherein each number used as an MSRN is routed towards an entity that is capable of receiving calls, which uses the information in the received call to capture the identification information.

The method of any of the claims 1 - 3, wherein each number used as an MSRN is forwarded to one or more other numbers which are in turn routed towards an entity that is capable of receiving calls, which uses the information in the received call to capture the identification information.

The method of any of the claims 1 - 3, wherein each number used as an MSRN is forwarded to one or more other numbers which are in turn defined in the HLR with CAMEL TCSI enabled towards a CAMEL capable entity, which uses the information in the CAMEL TCSI trigger to capture the identification information .

The method of any of claims 5,7 or 8 modified by cascading any number of call forwards.

A system for detecting the MSISDNs used by International Gateway Bypass (SIM Box) operators, the system comprising : an IDD Bypass Detection Server (IBD Server) capable of assuming the VLR function; location updating any number of roaming SIMs in the IBD Server; generating calls to the MSISDNs of the roaming SIMs location updated in the IBD Server; issuing MSRNs for each PRN (provide roaming number) request received as a result of generating the calls; capturing identification information associated with the calling party of the calls received for the roaming SIMs location updated in the IBD Server. The system of claim 10, wherein the MSRNs issued are not in a real MSRN range instead in the range of normal MSISDNs of the mobile network (PLMN-A).

The system of claim 11, wherein the MSRNs issued are not in a contiguous range, but scattered arbitrarily in the number pool of the mobile network (PLMN-A).

The system of any of the claims 10 - 12 wherein each number used as an MSRN is defined in the HLR with CAMEL TCSI enabled towards the IBD Server, which uses the information in the CAMEL TCSI trigger to capture the identification information.

The system of any of the claims 10 - 12 , wherein each number used as an MSRN is defined in the HLR with call forwarding activated towards any number and CAMEL OCSI enabled towards the IBD Server, which uses the information in the CAMEL OCSI trigger to capture the identification information.

The system of any of the claims 10 - 12 wherein each number used as an MSRN is routed towards the IBD Server, which uses the information in the received call to capture the identification information . The system of any of the claims 10 - 12 , wherein each number used as an MSRN is forwarded towards one or more other numbers which are in turn routed towards the IBD Server, which uses the information in the received call to capture the identification information .

The system of any of the claims 10 - 12 , wherein each number used as an MSRN is forwarded to one or more other numbers which are in turn defined in the HLR with CAMEL TCSI enabled towards the IBD Server, which uses the information in the CAMELTCSI trigger to capture the identification information

[Claim 18] The system of any of claims 14,16 or 17 modified by cascading any number of call forwards.

[Claim 19] The system of any of claims 10-17 where the identified information is used to automatically block the calls generated by the International Gateway Bypass (SIM Box) operators.

[Claim 20] The system of any of claims 10-17 where the identified information is used to block the calls generated by the International Gateway Bypass (SIM Box) operators, by sending that information to a call screening device and / or the HLR or SCF or any other network node in the PLMN-A.

[Claim 21] The system of any of claims 10-17 where the captured information is sent to a Web Server, enabling the users to view the information using a web browser.