LTE Handover Tunnel Setup for User Plane Data

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Solution Overview

Problem

In LTE mobile communication systems, during handovers, all GTP tunnels are set up between the handover-source and handover-target radio base stations, regardless of whether user plane data exists, leading to wasteful resource usage.

Innovation Solution

A method where the handover-source radio base station judges and notifies the handover-target radio base station about the existence of user plane data for each access bearer, and only sets up a data forwarding tunnel for bearers with existing data, eliminating redundant tunnel setups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GTP tunnels are set up for all access bearers during handover, then user plane data can be forwarded for all bearers, but resources are wasted due to unnecessary tunnel setups

Engineering Contradiction:
Improvedata forwarding completenessVSAvoidresource usage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the set of all access bearers into two subsets: those requiring data forwarding and those not requiring forwarding. By evaluating each bearer individually and setting up GTP tunnels only for bearers with pending data, the system avoids the resource waste of creating tunnels for all bearers while ensuring complete data forwarding for those that need it.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing the action of setting up GTP tunnels for all access bearers (excessive action), the patent applies partial action by selectively setting up tunnels only for the subset of bearers that actually require data forwarding. This reduces resource consumption while maintaining the necessary functionality.

Inventive Principle:
Principle #16Partial or excessive action

2Ease of operation

If GTP tunnels are set up for all access bearers, then data forwarding is simplified, but system complexity increases due to unnecessary tunnel management

Engineering Contradiction:
Improvedata forwarding processVSAvoidtunnel management
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent divides access bearers into categories based on data forwarding requirements. By processing bearers selectively rather than uniformly, the system reduces the number of tunnels that need to be managed and configured, thereby lowering system complexity while maintaining ease of operation for the necessary bearers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts and identifies the specific subset of access bearers that require data forwarding by evaluating pending data conditions. This extraction allows the system to focus tunnel management efforts only on the necessary bearers, reducing overall system complexity while preserving the ease of operation for critical data paths.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If GTP tunnels are set up for all access bearers, then handover can proceed without additional evaluation, but resource efficiency decreases

Engineering Contradiction:
Improvehandover speedVSAvoidresource allocation
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent performs preliminary evaluation of each access bearer to determine whether user plane data exists before initiating the handover process. By pre-identifying which bearers require data forwarding, the system can set up only the necessary GTP tunnels, reducing resource allocation while maintaining efficient handover execution.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of setting up GTP tunnels for all access bearers during handover (excessive action), the patent applies partial action by creating tunnels only for the specific subset of bearers that have pending user plane data. This approach reduces resource consumption while ensuring that handover productivity is maintained for the necessary data paths.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2214360B1Mobile communication method and radio base stations
Publication Date: 2016.06.29 NTT DOCOMO INC
  • EP2214360B1 patent drawingFigure 1~2
  • EP2214360B1 patent drawingFigure 3
  • EP2214360B1 patent drawingFigure 4

AI summary

A radio base station (T-eNB) according to the present invention is configured to set up a data forwarding tunnel for forwarding user plane data to the radio base station (T-eNB) only for an access bearer for which the user plane data to be forwarded exists, when receiving a notification from a handover-source radio base station (S-eNB) as to whether or not the user plane data to be forwarded exists for each access bearer, the notification being made by using a handover request message for the mobile station (UE), and the access bearer being set up between the radio base station (T-eNB) and a upper level node (SGW); and