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Browse Prior Art Database

NEW STRATEGY FOR FRAUD DETECTION IN CELLULAR NETWORKS

IP.com Disclosure Number: IPCOM000008784D
Original Publication Date: 1998-Sep-01
Included in the Prior Art Database: 2002-Jul-12
Document File: 3 page(s) / 214K

Publishing Venue

Motorola

Related People

Baruch Altman: AUTHOR

Abstract

This article offers a new perspective on fraud detection and prevention in cellular networks. The new strategy is especially effective in no-roaming cellular applications, such as Wireless Local Loop (WLL) networks. The new strategy advocates de-centralization by delegating responsibility for the fraud detection to the cellular terminals themselves. This approach is also object oriented in that it empowers the objects (cellular terminals) to be trig- gered into operating on their own properties.

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8 MOTOROLA

Technical Developments

NEW STRATEGY FOR FRAUD DETECTION IN CELLULAR NETWORKS

by Baruch Altman

  This article offers a new perspective on fraud detection and prevention in cellular networks. The new strategy is especially effective in no-roaming cellular applications, such as Wireless Local Loop (WLL) networks. The new strategy advocates de-centralization by delegating responsibility for the fraud detection to the cellular terminals themselves. This approach is also object oriented in that it empowers the objects (cellular terminals) to be trig- gered into operating on their own properties.

  Cellular networks have long been subjected to cellular fraud, resulting in heavy losses in income to the cellular operators and service degradation to the cellular subscribers. Using simple tools infinite number of illegal cellular terminals may be repro- duced from one legitimate cellular terminal. This operation is usually referred to as "cloning". The clone terminals pretend to be the original one by using its identification keys (such as mobile number and Electronic Serial Number). Therefore, they are viewed by the centralized service facilities (Base Site, switch, etc..) as if they were the original legiti- mate one. The clone terminals are serviced in the cellular network as if they were the legal original one, and are primarily used for initiating outgoing calls. Normally, these calls would be paid for by the cellular operator who thus soaks the losses of the fraud. From the subscriber point of view, the clone terminals may cause problems ranging from service degradation to harrassment to a complete service storage.

  Initially, cellular networks were not designed for handling the cloning fraud. The major problem being the detection - how to differentiate the legal cellular terminal from its clone siblings. Once the fraudulent terminal is identified, proper actions such as denying service can be taken.

Cellular service is granted via exchange of iden- tification keys between the cellular terminal and the

cellular service provider station (referred to as Base Site - BS). Air interfaces that use a common signalling channel for this exchange are more vulnerable to cloning since listening on constant predetermined channels is easy. More so in air inter- faces that do not use sophisticated mechanisms to protect the exchanged identification keys (such as digital encryption). The outcome has been that the early analogue air interfaces (TACS, AMPS, NMT, etc.) are very vulnerable to cloning.

  Over time, several mechanisms for guarding against cloning were introduced into existing cellu- lar networks, while new air interfaces, such as CDMA, have been pre-designed with this issue in mind. As with any other criminal activity, fraudul~ent calls can be guarded against in two main phases: prevention and detection. Prevention is, of course, the preferred phase as the fraudulent call is being completely avoided. An example for a prevention attempt i...