VoIP Call Processing System Using SIP Signaling for Fraud Detection

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Solution Overview

Problem

Existing communication systems in controlled-environment facilities, particularly prisons, face challenges in detecting fraudulent telephone activity using Voice over Internet Protocol (VoIP) due to the obsolescence of legacy three-way call detection techniques, which are ineffective in packet-switch paradigms and silence suppression environments.

Innovation Solution

A call processing system that utilizes Session Initiation Protocol (SIP) signaling to detect abnormal and disallowed activity by monitoring both VoIP voice data packets and SIP signaling packets, enabling detection of illicit activities such as call forwarding, call redirect, and call transfer, and integrates with a Jail Management Server for real-time monitoring and corrective actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If legacy three-way call detection techniques are used in VoIP environments, then detection capability is maintained, but detection effectiveness deteriorates due to packet-switch paradigm and silence suppression

Engineering Contradiction:

Improvedetection effectivenessVSAvoidadaptability to VoIP environment

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the detection parameters from acoustic-based (sound detection, hookflash detection) to signaling-based (SIP message analysis). By monitoring SIP signaling messages rather than audio parameters, the system adapts to the packet-switched VoIP paradigm and remains effective despite silence suppression techniques.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/acoustic detection mechanism with an information-processing mechanism. Instead of detecting physical sounds like hookflash or silence patterns, the system analyzes SIP signaling messages to detect call manipulation attempts, substituting acoustic detection with digital signal analysis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If sound detection techniques are used to detect three-way calling, then detection capability is provided, but false positives increase and detection precision decreases

Engineering Contradiction:

Improvedetection precisionVSAvoidfalse positives

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces SIP signaling messages as an intermediary for detection. Instead of directly analyzing audio signals that can be misleading, the system uses SIP messages as an intermediate layer that provides more reliable information about call manipulation attempts, reducing false positives.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system continuously monitors SIP signaling messages and provides feedback about call status and manipulation attempts. By analyzing the signaling protocol's built-in feedback mechanisms, the system can accurately detect three-way calling and other call manipulations without the false positives associated with acoustic detection.

Inventive Principle:

Principle #23Feedback

3Reliability

If comprehensive monitoring of SIP signaling is implemented, then detection capability for illicit activity is improved, but system complexity increases

Engineering Contradiction:

Improvedetection capabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the SIP signaling monitoring system multi-functional. The same SIP message analysis infrastructure detects multiple types of illicit activity including three-way calling, call forwarding, call redirect, and call transfer. This universal approach improves detection capability without proportionally increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system segments the SIP message analysis into distinct detection modules for different call manipulation types. By organizing detection logic into separate, manageable segments (three-way call detection, forwarding detection, redirect detection), the system maintains high detection capability while managing complexity through modular architecture.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11778091B2Utilizing sip messages to determine the status of a remote terminal in VOIP communication systems

Publication Date: 2023.10.03 GLOBAL TEL LINK CORP

AI summary

There is a growing problem in correctional facility telecommunications systems in which parties on a voice call may connect inmate callers with restricted parties. Prison communication systems monitor calls to prevent such activity, but in Voice over Internet Protocol (VoIP) environments such systems may fail to detect this activity. The present disclosure provides details of a system and method for using SIP messages common in VoIP environments to detect illicit activity initiated by a party on a voice call within a controlled environment. Scenarios are detected in which a called party connects an inmate caller to a restricted party via three-way call conferencing, call forwarding, or other call features. Corrective actions are then taken when such activity is detected, such as call blocking or alerting officials illicit activity is occurring.