Pre-handover Configuration for Inter-cell Handover Robustness

Solution Overview

Problem

The existing handover process in HetNet scenarios experiences low handover success rates and poor robustness due to long waiting times, leading to handover failures when UE moves between macro and small cells, especially under high interference conditions.

Innovation Solution

A method where UE receives pre-handover target cell configuration information from the serving cell, allowing it to initiate the handover procedure based on this information, including options to determine handover initiation time based on pre-handover indication, handover time indication, or specific conditions such as successful Measurement Report (MR) and Handover Command (HO CMD) reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the existing handover procedure is used with long waiting time (TTT+handover preparation time), then the handover decision can be made with sufficient measurement accuracy, but the UE may go deep into the target cell and fail to receive HO CMD due to excessive interference, causing handover failure

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidhandover success rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent performs handover preparation in advance before the actual handover execution. The source cell initiates handover preparation with the target cell, obtains handover configuration information, and sends it to the UE提前. This allows the UE to have the handover command ready before entering the high interference region, resolving the contradiction between needing time for accurate measurement and avoiding failure due to long waiting time in high interference environments

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the waiting time is reduced to avoid deep entry into target cell, then handover robustness is improved, but the measurement accuracy and reliability of handover decision may be compromised

Engineering Contradiction:

Improvehandover robustnessVSAvoidhandover decision reliability

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent performs handover preparation in advance before the actual handover execution. The source cell initiates handover preparation with the target cell, obtains handover configuration information, and sends it to the UE提前. This allows the UE to have the handover command ready before entering the high interference region, resolving the contradiction between needing time for accurate measurement and avoiding failure due to long waiting time in high interference environments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the handover process into two separate phases: handover preparation phase and handover execution phase. The preparation phase includes measurement, decision, and configuration acquisition, while the execution phase involves applying the configuration and completing handover. This segmentation allows measurement accuracy to be ensured in the preparation phase while execution happens quickly when needed, resolving the time accuracy contradiction

Inventive Principle:

Principle #1Segmentation

3Area of stationary object

If the existing handover procedure is used in HetNet scenario with macro and small cells, then the network can provide extended coverage, but the long handover preparation time causes UE to experience excessive interference from the target cell

Engineering Contradiction:

Improvenetwork coverage areaVSAvoidinterference from target cell

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent performs handover preparation in advance before the actual handover execution. The source cell initiates handover preparation with the target cell, obtains handover configuration information, and sends it to the UE提前. This allows the UE to have the handover command ready before entering the high interference region, resolving the contradiction between needing time for accurate measurement and avoiding failure due to long waiting time in high interference environments

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3029986B1Pre-switching processing method and device, user equipment and cell

Publication Date: 2019.02.20 ZTE CORP

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AI summary

Provided are a method and device for processing pre-handover, User Equipment (UE) and a cell. The method includes that: UE receives pre-handover target cell configuration information sent by a serving cell; and the UE executes pre-handover procedure according to the pre-handover target cell configuration information. By the disclosure, the problems of low handover success rate and poor handover robustness of inter-cell handover in the related art are solved, and effects of enhancing robustness of inter-cell handover, increasing a success rate of inter-cell handover and improving network performance and a user experience are further achieved.