Browse Prior Art Database

Tracking Handset without EIR

IP.com Disclosure Number: IPCOM000125533D
Published in the IP.com Journal: Volume 5 Issue 6B (2005-07-10)
Included in the Prior Art Database: 2005-Jul-10
Document File: 5 page(s) / 75K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In GSM technology, the identities of subscriber and mobile equipment are separate. This makes the theft of GSM mobile telephones attractive, since the stolen handset can be reused simply by using any valid SIM (Subscriber Identity Module). Also, only a subscriber but not the mobile equipment can be barred by the operator. Typically, the tracking of handsets is realized through the network element Equipment Identity Register (EIR). This approach in the EIR is shown in Fig. 1, outlining the process of an equipment check between MSC/VLR (Mobile Switching Center / Visitor Location Register) and EIR. Alternatives are highlighted in the following paragraphs.

A) Usage of CAMEL (Call Management Language) Phase 4 PSI (Provide Subscriber Information) call flow to track a stolen handset To get familiar with some functions, here an introduction to ATI (Any Time Interrogation) and PSI MAP (Provide Subscriber Information Mobile Application Part) messages is given. The MAP message ATI is sent from the gsmSCF (GSM Service Control Function) to the HLR (Home Location Register) requesting the location information and/or the subscriber status of a particular subscriber. The HLR relays the request to the VLR through the MAP (Mobile Application Part) message PSI. The received PSI response message is then forwarded by the HLR to the requesting gsmSCF in the ATI response message. The handling of this nested dialogue is depicted in Fig. 2.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 27% of the total text.

Page 1 of 5

S

Tracking Handset without EIR

Idea: Bindu Akam, IN-Bangalore; Hema G, IN-Bangalore; Manohar SL, IN-Bangalore; Pritish

Banerjee, IN-Bangalore

In GSM technology, the identities of subscriber and mobile equipment are separate. This makes the theft of GSM mobile telephones attractive, since the stolen handset can be reused simply by using any valid SIM (Subscriber Identity Module). Also, only a subscriber but not the mobile equipment can be barred by the operator. Typically, the tracking of handsets is realized through the network element Equipment Identity Register (EIR). This approach in the EIR is shown in Fig. 1, outlining the process of an equipment check between MSC/VLR (Mobile Switching Center / Visitor Location Register) and EIR. Alternatives are highlighted in the following paragraphs.

A) Usage of CAMEL (Call Management Language) Phase 4 PSI (Provide Subscriber Information) call flow to track a stolen handset

To get familiar with some functions, here an introduction to ATI (Any Time Interrogation) and PSI MAP (Provide Subscriber Information Mobile Application Part) messages is given. The MAP message ATI is sent from the gsmSCF (GSM Service Control Function) to the HLR (Home Location Register) requesting the location information and/or the subscriber status of a particular subscriber. The HLR relays the request to the VLR through the MAP (Mobile Application Part) message PSI. The received PSI response message is then forwarded by the HLR to the requesting gsmSCF in the ATI response message. The handling of this nested dialogue is depicted in Fig. 2.

The following are the enhancements in the ATI and PSI messages in the CAMEL Phase 4 standards:

- The PSI message can now be sent from the HLR to the SGSN (Serving GPRS Support Node) as well.

- The requesting of IMEI (International Mobile Equipment Identifier) in both the ATI and PSI request messages is allowed.

- Also, the IMEI data is transferred in both the PSI and ATI response messages.

As an enhancement in a PSI message with the CAMEL Phase 4, where the IMEI data is allowed to be requested, a stolen handset can be tracked. This solution requires that the HLR knows the IMEI of its subscribers. This will not be required if the subscriber can provide the IMEI when the handset is stolen.

For example, a subscriber with the connection from Operator 1 has lost his handset. Also for simplicity reasons it should be assumed that only two operators are acting in the geographical area of the subscriber. Now the subscriber notifies the theft of the handset to Operator 1 through the "legal means", the tracking of the handset is performed using the CAMEL Phase 4 PSI message as pointed out:

a) As a first step, Operator 1 tries to track the handset in his own network by sending the PSI request message to the VLR/SGSN requesting the IMEI, on all the IMSIs (International Mobile Subscriber Identities) belonging to Operator 1. If the IMEI received in the PSI response message matches with the repor...