More Information

Introduction

Lawful Intercept (LI) or CALEA (Communications Assistance to Law Enforcement Act) represent regulation requiring mobile network operators to enable legally authorized surveillance of communications.  This means a "wireless tap" of the communications channel for voice and/or data communications. LI is being considered in Europe and is being mandated in the USA in 2002.

Research

Wholesale Mobile Report

Secrets of MVNO Success

Mobile in Minute papers

Challenges

Being "unwired", mobile communications is substantively more difficult to tap into than fixed networks. For one, the user may be using service anywhere that the home operator and its roaming partners support service. Consequently, there is a need to determine the presence, identity, and location of callers prior to tapping, as it would otherwise be prohibitively difficult (and a privacy issue) to attempt to tap all calls, merely to filter out those calls that are requiring monitoring by legally authorized personnel.

SS7 networks must be monitored themselves to search for the presence, identity, location, and status of callers. Both call set-up (ISUP) as well as database application (TCAP) components of SS7 networks must be monitored as a means of detecting call placement and/or service or feature interaction. This facilitates a fast set up and operation of a tapping.

Importance of LI

With security being a top priority of government due to terrorist activities, the ability to lawfully monitor communications is of utmost importance to security and law enforcement officials. Other important and related security capabilities include enhanced wireless emergency calling and priority access calling. All of these capabilities are driven by regulatory activities within government.

Technical Issues

There is a need for Administration, Access, Delivery and Collection of Data.

There is a need for Administration in the form of provisioning the tap into the wireless call.  This will largely be handled as an administrative function as discussed in the next section.

There is a need for Access in terms of interception of the call and call data.  Both call (bearer communications) data and signaling data must be somehow captured.  The Delivery function entails capture and conversion of the data into a required legal intercept standard format, which may be delivered to law enforcement monitoring facilities.  Collection pertains to monitoring call-identifying (signaling) and call content (bearer) information.   The relavent standards include J-STD-025A and ETSI TS 101 671.

More than a Technical Solution Required

A solution is required to mediate the relationship between the requesting agencies (such as the FBI in the US) and the mobile network operators. As many request for LI will undoubtedly result from enforcement of security procedures, there is a need for an intermediary organization or business entity to manage request for intercept and monitoring.

Additional Resources:

Books about: Public Safety and Homeland Security

For information about SS7 technology and related applications: Data on SS7 (click here)