Emergency Callback Suppression via GMSC Protocol Override

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Solution Overview

Problem

Existing emergency callback systems in wireless networks can be hindered by call blocking features, which are undesirable during emergency situations, making it impractical for subscribers to disable them in time, especially for PSAP responders.

Innovation Solution

The system employs ISDN User Part (ISUP) and CAMEL protocol parameters to initiate special Mobile Application Part (MAP) messages between a gateway mobile switching center (GMSC) and a home location register (HLR), creating a special-use SendRoutingInformation (SRI) message to suppress call blocking features, ensuring emergency callbacks can proceed without interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If call blocking features are enabled for subscribers, then call management control is improved, but emergency callback reliability deteriorates

Engineering Contradiction:

Improvecall management controlVSAvoidemergency callback reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system applies preliminary anti-action by detecting emergency callback attempts and proactively disabling call blocking features before they can interfere with the emergency communication. The GMSC identifies emergency callbacks through specific routing information and pre-emptively overrides subscriber-defined call restrictions, ensuring emergency calls can proceed without being blocked by previously enabled call management features.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The GMSC acts as an intermediary between the PSAP and the mobile switching center, mediating the conflict between call blocking features and emergency callback needs. It receives emergency callback requests from the PSAP, disables call restrictions through protocol messages to the HLR, and forwards the callback without interference, thus resolving the contradiction between subscriber control and emergency reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If subscribers manually disable call blocking features before emergency calls, then emergency callback reliability is improved, but response time and ease of operation worsen

Engineering Contradiction:

Improveemergency callback reliabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system implements self-service by automatically detecting and disabling call blocking features without requiring subscriber action. When an emergency callback is initiated by the PSAP, the GMSC autonomously identifies the need to override restrictions and performs the disabling through protocol messages, eliminating the time-consuming manual intervention that would otherwise be required from the subscriber.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs preliminary action by pre-configuring the network to automatically recognize and handle emergency callback scenarios. The GMSC is pre-programmed to identify emergency callbacks through specific routing information and to automatically disable call restrictions before the actual emergency communication begins, ensuring no time is lost to manual configuration during critical moments.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If automatic elimination of call blocking features is implemented, then emergency callback reliability is improved, but system complexity increases

Engineering Contradiction:

Improveemergency callback reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses parameter changes to implement automatic elimination of call blocking features. The GMSC modifies protocol parameters (such as disabling specific service indicators in MAP messages) to override call restrictions during emergency callbacks. By changing these technical parameters dynamically, the system achieves reliable emergency communication without requiring complex hardware modifications or additional infrastructure.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8886154B2Systems and methods for providing emergency callback procedures

Publication Date: 2014.11.11 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Enhanced services, such as call restriction, call forwarding, anonymous call rejection, and proprietary services, may interfere with an emergency callback potentially preventing the callback from reaching the intended destination. Systems and methods for processing emergency calls to eliminate emergency callback failure in response to an emergency call being released are provided herein.