Cell Handover Command Carrying TDD Slot Configuration

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Solution Overview

Problem

In LTE systems, cell handover cannot be implemented when the target cell operates in the TDD mode due to the UE's inability to acquire TDD timeslot configuration information, hindering normal system operation.

Innovation Solution

A cell handover method where the TDD timeslot configuration information of the target cell is carried in the cell handover command, allowing the UE to deduce the necessary parameters for control channels and complete the handover without acquiring this information from a system broadcast, ensuring successful handover even in TDD mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE fetches system information of the target cell during handover, then the UE can acquire TDD timeslot configuration information, but this causes delay due to interruption of the handover

Engineering Contradiction:
Improvehandover completionVSAvoidhandover delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The TDD timeslot configuration information of the target cell is pre-loaded into the cell handover command by the source cell before the UE performs handover. This allows the UE to obtain the configuration information in advance without needing to fetch it from the target cell during the handover process, thereby eliminating handover interruption delay while ensuring reliable handover completion.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the TDD timeslot configuration information is not included in the cell handover command, then the handover command size is reduced, but the UE cannot deduce control channel parameters in TDD mode

Engineering Contradiction:
Improvehandover efficiencyVSAvoidparameter deduction capability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The source cell pre-loads the TDD timeslot configuration information into the cell handover command before transmission to the UE. This preliminary action ensures that the UE receives the necessary configuration information in advance, enabling it to successfully deduce control channel parameters and complete the handover process in TDD mode without additional delays.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the cell handover command includes TDD timeslot configuration information, then the UE can complete handover in TDD mode, but the handover command size increases

Engineering Contradiction:
ImproveTDD mode handover capabilityVSAvoidhandover command size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts only the essential TDD timeslot configuration information from the complete system information of the target cell and includes only this extracted subset in the cell handover command. This selective extraction approach enables the UE to complete handover in TDD mode while minimizing the increase in handover command size by including only the necessary parameters.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If the UE acquires TDD timeslot configuration from system broadcast, then the information is accurate, but the handover process is interrupted

Engineering Contradiction:
Improveconfiguration information accuracyVSAvoidhandover interruption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The source cell obtains and pre-loads the TDD timeslot configuration information from the target cell's system broadcast before the UE initiates handover. By performing this information acquisition in advance, the configuration accuracy is maintained while the UE receives the pre-loaded information in the handover command, eliminating any interruption during the actual handover execution.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2237607B1Method and apparatuses for implementing cell handover
Publication Date: 2014.10.08 CHINA ACAD OF TELECOMM TECH
  • EP2237607B1 patent drawingFigure 1~2
  • EP2237607B1 patent drawingFigure 3~4
  • EP2237607B1 patent drawingFigure 5~6

AI summary

It is disclosed a method and system for implementing a cell handover, which are used to solve the problem in the prior art that the cell handover can not be implemented when a target cell uses a TDD mode. The method for implementing the cell handover includes: when a user terminal needs perform the cell handover, a network side sending a cell handover command to the user terminal; when the target cell uses the TDD mode and the cell handover command carries TDD slot configuration information of the target cell, the user terminal implementing the cell handover according to the TDD slot configuration information in the cell handover command. It is further disclosed a user terminal and a Base Station, which are used to implement the cell handover in a TDD system.