Radio Terminal DRX Interval Control for Fast Handover

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Solution Overview

Problem

In radio communication systems, handovers during Discontinuous Reception (DRX) and Discontinuous Transmission (DTX) periods are challenging due to the delay in transitioning between states, which can result in service disruptions when a terminal moves beyond the current cell's range before receiving a handover indication.

Innovation Solution

The base station dynamically controls the DRX/DTX interval based on quality measurement reports from terminals, allowing for immediate handover indications during active intervals, even when the terminal is in a DRX/DTX state, by adjusting the DRX/DTX interval to ensure timely handover completion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the terminal is in DRX/DTX state to reduce power consumption, then power consumption is reduced, but handover processing is delayed because the terminal cannot receive handover indications during DRX/DTX periods

Engineering Contradiction:
Improvepower consumptionVSAvoidhandover processing time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent dynamically adjusts the DRX/DTX interval based on terminal mobility conditions. When handover is detected or suspected, the system shortens the DRX/DTX interval to ensure the terminal remains awake long enough to receive handover indications, while maintaining longer intervals during stable conditions to conserve power.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary actions by detecting handover conditions (such as measurement reports indicating poor signal quality) before the terminal actually moves out of coverage. This allows the system to proactively adjust DRX/DTX settings in advance, ensuring the terminal will be awake when needed for handover processing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the DRX/DTX interval is extended to allow handover processing, then handover can be completed, but power consumption increases due to longer active periods

Engineering Contradiction:
Improvehandover completionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the DRX/DTX interval parameter dynamically based on terminal conditions. The system monitors signal quality and mobility indicators, then adjusts the DRX/DTX interval to the minimum necessary value to complete handover, avoiding unnecessarily long active periods that would increase power consumption.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the terminal frequently transitions between RRC states to adapt to mobility, then adaptability to different conditions is improved, but the complexity of state management increases

Engineering Contradiction:
Improveadaptability to mobility conditionsVSAvoidstate management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements periodic monitoring of signal quality and handover conditions, with systematic adjustments to DRX/DTX intervals based on predefined criteria. This structured approach to state management reduces complexity by following regular patterns rather than requiring complex real-time decisions.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2034633B1Radio communication terminal device, radio communication base station device, and radio communication method
Publication Date: 2018.08.22 GODO KAISHA IP BRIDGE 1
  • EP2034633B1 patent drawingFigure 1
  • EP2034633B1 patent drawingFigure 2
  • EP2034633B1 patent drawingFigure 3

AI summary

It is possible to provide a radio communication terminal device, a radio communication base station device, and a radio communication method capable of rapidly completing a handover even during DRX/DTX. In the devices and the method, a terminal (100) transmits a quality measurement result to a base station (150) at an Active interval. Here, the terminal (100) sets the DRX/DTX interval to a short interval since performance of a handover is predicted. The base station (150) which has received the quality measurement result transmitted from the terminal (100) recognizes that the terminal has set the DRX/DTX interval to a short interval and transmits a handover instruction to the terminal (100) at the Active interval, considering the shortened DRX/DTX interval.