X2 Interface Cell Status Exchange for Handover Optimization

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Solution Overview

Problem

During handover scenarios in E-UTRAN networks, source eNBs lack information about the availability and capability of neighboring cells, leading to potential handover failures or delays due to unnecessary signaling and increased load on the X2 interface.

Innovation Solution

Implementing a method where access nodes exchange information about neighboring cell availability and capabilities over the X2 interface, either periodically or triggered by events like hardware failures, to inform handover decisions and radio resource control operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If source eNB sends handover request to target eNB without prior cell status information, then handover decision can be made quickly, but handover may fail or require re-attempt due to target cell unavailability

Engineering Contradiction:
Improvehandover execution timeVSAvoidhandover success rate
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The source eNB receives and stores cell status information (availability, capability, load) from neighboring eNBs before handover is needed. This preliminary acquisition of information allows the source eNB to make informed handover decisions without requiring time-consuming requests to target eNBs, thereby reducing handover execution time while ensuring reliability by avoiding selections of unavailable cells

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If source eNB requests handover to target cell without knowing its capability, then signaling is simple, but handover may fail due to feature incompatibility

Engineering Contradiction:
Improvesignaling complexityVSAvoidhandover compatibility
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The source eNB receives capability information (supported features, functions) from neighboring eNBs in advance through the X2 interface. This preliminary knowledge allows the source eNB to assess feature compatibility before initiating handover, ensuring reliable compatibility matching without adding complex real-time signaling exchanges

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If source eNB does not have neighbor cell availability information, then X2 interface signaling load is low, but unnecessary handover requests increase overall signaling

Engineering Contradiction:
ImproveX2 interface signaling loadVSAvoidunnecessary signaling
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The source eNB receives cell status information (availability, capability, load) from neighboring eNBs in advance through periodic or event-triggered updates on the X2 interface. By having this information ready, the source eNB can filter out unsuitable target cells before initiating handover requests, thereby preventing unnecessary signaling traffic and reducing overall network signaling load

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If UE measures all neighboring cells without availability information, then cell selection is comprehensive, but power consumption increases

Engineering Contradiction:
Improvecell selection completenessVSAvoidUE power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The source eNB receives and stores cell status information from neighboring eNBs before UE measurement and selection. Based on this preliminary information about cell availability and capability, the source eNB can provide a filtered neighbor cell list to the UE, directing it to measure only viable cells. This approach maintains comprehensive cell selection among suitable cells while significantly reducing UE power consumption by eliminating measurements of non-viable cells

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2115969B1Method and apparatus providing inter-node b signalling of cell status information
Publication Date: 2015.06.03 NOKIA TECHNOLOGIES OY
  • EP2115969B1 patent drawingFigure 1
  • EP2115969B1 patent drawingFigure 2
  • EP2115969B1 patent drawingFigure 3

AI summary

In an exemplary aspect of the invention there is a method comprising receiving cell- related information from a first access node at a second access node, and using the cell- related information during at least one of a handover and a radio resource control (RRC) related operation. Where the use of the exemplary embodiments of this invention include, but are not limited to, reducing handover execution time, reducing the signaling load related to an unsuccessful handover and/or radio resource control related procedures, and reducing the need of a user equipment to measure unnecessary cells.