Selective PDN Context Pre-registration for LTE to eHRPD Handover

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Solution Overview

Problem

Existing wireless communication systems face challenges in maintaining session continuity when user equipment transitions from LTE to eHRPD coverage, leading to potential service discontinuity due to the time required to establish a new Packet Data Network (PDN) and Quality of Service (QoS) context, which can take several tens of seconds, and results in increased traffic on the LTE air interface and core network.

Innovation Solution

The solution involves selective pre-registration of the packet data context with the eHRPD network while still camped on the LTE network, optimizing the process by creating a pre-registration PDN/QoS context only for a subset of connections, delaying full registration until necessary, and avoiding unnecessary burdens on the system, thereby reducing traffic load and minimizing service disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If full PDN and QoS context registration is performed when transitioning from LTE to eHRPD, then session continuity is maintained, but registration time increases to several tens of seconds and traffic load on LTE air interface and core network increases

Engineering Contradiction:

Improvesession continuityVSAvoidregistration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing selective pre-registration of packet data context with the eHRPD network while the user equipment is still camped on LTE network. This advance preparation creates a pre-registration PDN/QoS context that will be available immediately when handoff occurs, eliminating the need for time-consuming registration procedures after transition and thus reducing registration time while maintaining session continuity

Inventive Principle:

Principle #10Preliminary action

2Reliability

If full PDN and QoS context registration is performed when transitioning from LTE to eHRPD, then session continuity is maintained, but traffic load on LTE air interface and core network increases

Engineering Contradiction:

Improvesession continuityVSAvoidtraffic load

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by implementing selective pre-registration that creates PDN/QoS context only for a subset of connections rather than all connections. This selective approach prepares only the necessary packet data contexts in advance, reducing the overall traffic load on LTE air interface and core network while still ensuring session continuity for critical services during handoff

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8432872B2Creating PDN context in EHRPD network over a LTE tunnel

Publication Date: 2013.04.30 QUALCOMM INC

AI summary

Pre-registration involves establishing and maintaining the same Packet Data Network (PDN)/Quality of Service (QoS) context that exists in a 3GPP Long Term Evolution (LTE) network via a data tunnel in a 3GPP2 evolved High Rate Packet Data (eHRPD) network. To avoid undue increases in the traffic on a LTE Air Interface and core network, optimizations selectively complete the PDN context only for a subset of the PDN connections, only when close to performing a handover, or other trigger conditions.