L2TPv3 Pseudo Wire Handoff Latency Reduction

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Solution Overview

Problem

Communication systems face handoff delays and packet loss when mobile devices move between neighboring geographic cells due to the labor-intensive and error-prone manual configuration of access nodes, and the inability to directly communicate with target access nodes, leading to quality degradation or dropped voice communications.

Innovation Solution

The use of L2TPv3 pseudo wires to encapsulate signaling and user traffic between base stations in an IP architecture, allowing for handoff facilitation through the establishment of CCP links and neighbor alerts between access routers, enabling communication via current access routers until a direct link is established with the target access router.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual configuration is used to set up access nodes and neighbor relationships, then network connectivity can be established, but the process becomes labor-intensive and error-prone

Engineering Contradiction:
Improvehandoff reliabilityVSAvoidconfiguration effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system enables access nodes to automatically discover and configure neighbor relationships without manual intervention. The target access node autonomously responds to handoff requests by providing its address information, eliminating the need for labor-intensive manual configuration while maintaining reliable connectivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system pre-establishes the capability for automatic neighbor discovery and configuration. By designing the protocol to inherently support autonomous address exchange between access nodes, the system prepares the network in advance to handle handoffs without manual setup, reducing both configuration effort and potential errors

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the end node maintains a single bidirectional communications link, then connection simplicity is preserved, but handoff delays and packet loss occur

Engineering Contradiction:
Improveconnection managementVSAvoidhandoff latency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The system pre-establishes a tunnel between the source and target access nodes before the handoff is complete. This preliminary setup of the forwarding path allows the end node to switch connections without delay, as the communication path is already prepared and configured in advance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a tunnel as an intermediary mechanism that bridges the source and target access nodes. This tunnel acts as a mediator that forwards packets during the handoff transition, enabling seamless connection switching without requiring the end node to manage complex multi-link transitions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the end node cannot communicate directly with the target access node, then network security and control are maintained, but communication continuity is interrupted during handoff

Engineering Contradiction:
Improveservice continuityVSAvoidcommunication path
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tunnel between access nodes serves as an intermediary that enables indirect communication during handoff. Packets are forwarded through this tunnel from the source access node to the target access node, maintaining service continuity while preserving the security model that restricts direct end-to-end communication

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The communication path through the tunnel is established in advance before the handoff completes. This preliminary setup ensures that when the end node switches from the source to target access node, communication continuity is maintained without interruption, as the forwarding path is already in place

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2014126B1Apparatus and device for mobility management
Publication Date: 2016.09.21 QUALCOMM INC
  • EP2014126B1 patent drawingFigure 1
  • EP2014126B1 patent drawingFigure 2
  • EP2014126B1 patent drawingFigure 3

AI summary

Embodiments describe mobility management utilizing neighbor discovery and at least two pseudo wires. When a wireless device desires to handoff to a detected access router, such handoff may not be configured until such time as a current access router receives routing information of the target access router. In order to minimize handoff time, communication between the target access router and the wireless device can be through the current access router utilizing least two pseudo wires. Bidirectional neighbor discovery and create is conducted by the access routers allow subsequent wireless devices to automatically handoff between the access routers.