Call Screening System Using Signaling Interception

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Solution Overview

Problem

In commercial voice switching networks, especially in IDD wholesale networks, recipient operators face challenges in effectively screening and rejecting unwanted voice calls due to limited call screening capabilities and the complexities of processing real-time calls, which can lead to wasted network resources and difficulties in identifying anonymous call originators, particularly with the rise of VOIP and varying vendor capabilities.

Innovation Solution

A communication control system that uses a signaling tap and probe to extract and analyze signaling messages without disrupting standard network operations, allowing for call screening between different network operators, including mobile and fixed-line networks, by determining whether call parameters match predetermined criteria and releasing unwanted calls without altering the internal switch structure or routing arrangements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a voice switch operator routes calls to an inspecting system for screening, then call screening capability is improved, but device complexity and processing capacity consumption increase

Engineering Contradiction:

Improvecall screening capabilityVSAvoidrouting network arrangement complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a call screening system that acts as an intermediary between the originating voice switch and the recipient network. The system intercepts signaling messages (IAM, SAM, RLC) during call setup and independently determines whether to permit or reject the call based on screening criteria, without requiring complex routing modifications to the voice switch itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The call screening function is separated from the voice switch into an independent call screening system. This segmentation allows the voice switch to maintain its standard real-time call processing while the screening function is performed separately by analyzing signaling messages, thus reducing the complexity burden on the voice switch architecture.

Inventive Principle:

Principle #1Segmentation

2Reliability

If call screening is performed on real-time voice calls, then unwanted calls are rejected, but processing time is insufficient due to real-time establishment

Engineering Contradiction:

Improveunwanted call rejectionVSAvoidcall inspection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The call screening is performed during the call setup phase by analyzing signaling messages (IAM, SAM, RLC) before the voice call is fully established. The system extracts calling party information, called party information, and call type from these signaling messages and applies screening criteria in advance, allowing sufficient time for inspection without affecting real-time call quality.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If manual call screening is performed, then call control accuracy is improved, but operational cost increases due to huge manual resources required

Engineering Contradiction:

Improvecall control accuracyVSAvoidoperational cost

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The call screening system automatically performs call screening by extracting information from signaling messages and applying predetermined screening criteria without human intervention. The system autonomously determines whether to permit or reject calls based on the extracted parameters, eliminating the need for manual screening operations while maintaining high accuracy.

Inventive Principle:

Principle #25Self-service

4Reliability

If unconditional call forwarding is enabled to forward calls to a predetermined node for screening, then call screening is achieved, but user operation convenience deteriorates

Engineering Contradiction:

Improvecall screening functionVSAvoiduser operation convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The call screening system intercepts and analyzes signaling messages during the normal call setup process, allowing users to receive calls directly without enabling unconditional call forwarding. The screening decision is made transparently in the background based on the signaling message analysis, preserving user control over call forwarding while achieving screening objectives.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2866428B1Communication control system and communication control method

Publication Date: 2018.11.21 CITIC TELECOM INT HLDG

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AI summary

The present invention provides a communication control system and a communication control method. The communication control system comprises: a signaling extractor, configured to extract a signaling message between a first switch and a second switch; a signaling detector, configured to detect a specific message, which is sent by the first switch, in the signaling message and; and a call controller, configured to determine whether a specific parameter in the specific message meets a preset rule, when it is determined that the specific parameter meets the preset rule, the call controller sending to at least one of the first switch and the second switch a signaling message for releasing a call. The technology of the present invention can stop a malicious call without requiring massive or significant network routing changes.