QoS Flow Re-establishment During EVDO Handover

Solution Overview

Problem

When a mobile device moves from one EVDO subnet to another, there is a failure in transferring Quality of Service (QoS) flows, leading to degraded voice quality and signaling delays, especially during VOIP calls, as the QoS flows are not always properly transferred, causing subsequent calls to go on best effort flows.

Innovation Solution

A method in a mobile device to determine if it has moved from a first QoS-aware system to a second, requesting the de-allocation of existing QoS flows and initiating the reservation of new QoS flows in the second system, using specific messages and protocols like ReservationOFFRequest and GAUP sessions, to ensure proper QoS flow re-establishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mobile device assumes QoS flows will be transferred properly when moving between EVDO subnets, then the device can maintain simple operation, but QoS flow transfer fails leading to degraded voice quality and signaling delays

Engineering Contradiction:

Improveease of operationVSAvoidreliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The mobile device performs preliminary actions by requesting de-allocation of QoS flows in the target EVDO subnet before actually moving there, and proactively initiates reservation of QoS flows in advance. This preliminary action ensures that when the device actually moves between subnets, the QoS flows are already properly set up, preventing degradation in voice quality and signaling delays.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the mobile device requests de-allocation and initiates reservation of QoS flows during handover, then QoS flow transfer reliability is improved, but the handover process becomes more complex

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The QoS flow re-establishment process is segmented into distinct phases: first requesting de-allocation of QoS flows in the target EVDO subnet, then initiating reservation of QoS flows. This segmentation allows the complex handover process to be broken down into manageable steps, each handled by specific protocols like ReservationOFFRequest and GAUP sessions, making the overall process more controllable and reliable.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If QoS flows are not properly transferred during subnet movement, then the system can maintain simplicity, but subsequent calls go on best effort flows causing voice quality degradation

Engineering Contradiction:

Improvedevice complexityVSAvoidvoice quality degradation

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The mobile device performs preliminary actions by requesting de-allocation of QoS flows in the target EVDO subnet before actually moving there, and proactively initiates reservation of QoS flows in advance. This preliminary action ensures that when the device actually moves between subnets, the QoS flows are already properly set up, preventing degradation in voice quality and signaling delays.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8638752B2Method and system for handling QOS flows when moving between systems

Publication Date: 2014.01.28 MALIKIE INNOVATIONS LTD

AI summary

When a mobile device moves from a first QoS-aware system to a second QoS-aware system, QoS flows may or may not be moved properly. To deal with this, the mobile device requests de-allocation of flows in the second QoS-aware system, and then initiates reservation of flows in the second QoS-aware system. After this, the mobile device will know for certain which QoS flows exist in the second QoS-aware system and can behave accordingly.