Priority Call Bearer Management in Mobile Networks

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Solution Overview

Problem

In mobile communication systems, priority calls are not effectively prioritized for resource allocation, leading to failed or disconnected IMS call control signal bearers due to congestion, as existing systems fail to distinguish and manage priority calls differently from normal calls during paging and resource allocation processes.

Innovation Solution

A method involving a call control node that notifies a priority control node of priority calls, allowing the priority control node to change the priority of call control signal bearers to higher levels and perform preferential paging, ensuring that IMS call control signal bearers for priority calls are established and maintained before those for normal calls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the IMS performs paging for priority calls using existing procedures, then the paging can be initiated, but the priority call cannot be paged more preferentially than normal calls, leading to resource allocation failures

Engineering Contradiction:
Improvepriority call establishment reliabilityVSAvoidcall setup efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the parameter of call handling priority by introducing a priority indication in the Downlink Data Notification message. This parameter change enables the network to distinguish priority calls from normal calls and apply different handling procedures, thereby achieving preferential paging and resource allocation for priority calls while maintaining system productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If resources are allocated to IMS call control signal bearers without priority differentiation, then normal call processing is maintained, but priority calls fail to establish or maintain bearers during congestion

Engineering Contradiction:
Improvepriority call bearer maintenanceVSAvoidresource allocation mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a priority indication field as an intermediary element in the Downlink Data Notification message. This intermediary carries priority information from the call control node to the mobility management node, enabling indirect priority-based resource allocation without fundamentally redesigning the existing bearer establishment mechanism, thus maintaining reliability while controlling complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements dynamic resource allocation by allowing the mobility management node to adjust bearer allocation based on real-time priority information. When congestion is detected and priority calls are identified through the priority indication, the system dynamically shifts resource allocation to ensure priority call bearer maintenance, adapting to changing network conditions without fixed rigid rules.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the network treats all calls uniformly during congestion, then system simplicity is maintained, but priority calls experience the same resource allocation failures as normal calls

Engineering Contradiction:
Improvepriority call service qualityVSAvoidoverall call throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality differentiation by treating priority calls differently at specific points in the call flow where the priority indication is present. The mobility management node applies preferential handling only to bearers marked with priority indications, while normal bearers continue to follow standard procedures. This localized differentiation improves priority call service quality without requiring complete system redesign, thereby maintaining overall productivity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2523524B1Mobile communication method, call control node, priority control node, and mobile management node
Publication Date: 2016.11.02 NTT DOCOMO INC
  • EP2523524B1 patent drawingFigure 1
  • EP2523524B1 patent drawingFigure 2
  • EP2523524B1 patent drawingFigure 3

AI summary

The present invention provides the steps of: at a priority control node (PCRF), when reception of an invite signal including priority call information is notified from a call control node (P-CSCF), determining whether it is required to change the ARP of a call control signal bearer for sending the invite signal from a gateway (P-GW) to a mobile terminal (UE) to a higher ARP than the priority set in the call control signal bearer; when change of the ARP is determined to be required, changing the ARP of the call control signal bearer to a higher ARP than the ARP set in the call control signal bearer; and performing a paging for the mobile terminal (UE) according to the priority of the call control signal bearer.