Cell Handover Uplink Grant Scheduling Without Random Access

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Solution Overview

Problem

Existing communication systems in LTE face challenges in efficiently handing over a terminal apparatus from a source cell to a target cell without performing a random access procedure and allocating an uplink grant in advance, leading to inefficiencies in communication continuity.

Innovation Solution

A terminal apparatus and base station apparatus implementation that enables efficient handover by utilizing carrier aggregation, time division duplex, and frequency division duplex, along with advanced signaling and channel management to facilitate seamless communication through uplink grants and synchronization, allowing for simultaneous transmission and reception of multiple physical channels and signals across aggregated serving cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a terminal apparatus is handed over from source cell to target cell without performing random access procedure and without allocating uplink grant in advance, then handover delay is reduced, but communication reliability deteriorates

Engineering Contradiction:
Improvehandover delayVSAvoidcommunication reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by allocating uplink grant resources in advance as part of the handover command before the terminal actually needs to transmit uplink data in the target cell. This pre-allocation ensures that when handover occurs, the terminal can immediately use the pre-assigned uplink resources without needing to perform random access or wait for grant allocation, thus reducing handover delay while maintaining communication reliability through guaranteed uplink resources.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple physical channels and signals are transmitted simultaneously across aggregated serving cells, then communication efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecommunication efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the simultaneous transmission of multiple physical channels and signals across aggregated serving cells into separate processing stages. The terminal apparatus processes each serving cell's physical channels independently through distinct functional blocks, then combines the results. This segmented approach enables efficient multi-cell communication while managing device complexity by organizing the processing into manageable, modular components.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3432643B1Terminal apparatus, base station apparatus, and communication method
Publication Date: 2026.01.14 SHARP KK
  • EP3432643B1 patent drawingFigure 1
  • EP3432643B1 patent drawingFigure 2
  • EP3432643B1 patent drawingFigure 3

AI summary

A terminal apparatus 1 and a base station apparatus 3 efficiently continue to communicate with each other. The terminal apparatus 1 is a terminal apparatus to be handed over from a source cell to a target cell, and the terminal apparatus is handed over from the source cell to the target cell, and includes a receiver 13 configured to receive a higher layer information mobilityControlInfo including a first uplink grant and a subframe allocation information and a transmitter 13 configured to perform a transmission based on the first uplink grant in one of a plurality of subframes indicated by the subframe allocation information, wherein the subframe allocation information indicates at least one of the plurality of subframes associated with a set having the same number across radio frames.