Half-Duplex FDD Terminal Guard Period Management

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Solution Overview

Problem

In half-duplex frequency division duplex (FDD) communication systems, particularly in LTE, the transition from downlink to uplink and vice versa introduces frequency switching delays that affect guard periods, leading to uncertainties in terminal behavior and potential data transmission issues, as existing technologies do not adequately account for the frequency and power adjustment times during these switches.

Innovation Solution

A method where a terminal generates a guard period that considers the round trip time and switching time, including frequency and power adjustment times, to ensure no signal processing during the transition, thereby stabilizing the oscillator and maintaining data integrity by defining new terminal behaviors and scheduling configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the oscillator switches frequency from downlink to uplink, then the terminal can operate in half-duplex FDD mode, but an adjustment time is needed which changes the guard period and affects normal data transmission

Engineering Contradiction:
Improvehalf-duplex FDD operation capabilityVSAvoiddata transmission reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by defining guard periods in advance that account for the oscillator's frequency adjustment time. The guard period is configured to cover the time from when the oscillator starts switching frequencies until it becomes stable, ensuring that no data transmission occurs during this transition period. This prevents data loss or interference while maintaining half-duplex FDD operation capability.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the guard period is not changed correspondingly when the oscillator switches frequency, then the terminal structure remains simple, but normal data transmission and receiving are affected

Engineering Contradiction:
Improveterminal structure complexityVSAvoiddata transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the guard period duration based on the oscillator's frequency switching characteristics. When the oscillator switches between downlink and uplink frequencies, the guard period is extended to accommodate the adjustment time. This parameter adjustment ensures reliable data transmission without requiring complex terminal structure modifications.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the terminal defines new behaviors for guard period during frequency switching, then data transmission reliability is improved, but the terminal behavior complexity increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidterminal behavior complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the terminal to automatically manage its own guard period configuration based on its frequency switching state. The terminal monitors when the oscillator is switching frequencies and autonomously activates the appropriate guard period behavior without requiring complex external control or coordination. This self-managed approach improves reliability while minimizing the increase in terminal behavior complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3079428B1Half-duplex frequency-division duplex communication method, base station, and terminal
Publication Date: 2020.11.04 HUAWEI TECH CO LTD
  • EP3079428B1 patent drawingFigure 1~5
  • EP3079428B1 patent drawingFigure 6~8
  • EP3079428B1 patent drawingFigure 9~10

AI summary

Embodiments of the present invention provide a half-duplex frequency division duplex communication method, a base station and a terminal, including: when a terminal switches from a downlink subframe to an adjacent uplink subframe, generating a first guard period, where that the terminal does not process any signal in the first guard period is defined, that is, the terminal neither receives downlink data nor sends an uplink signal in the first guard period, and therefore uncertainty of a terminal behavior during a downlink-to-uplink switching process of the terminal is avoided, and successful sending of the uplink subframe can be ensured; and when the terminal switches from an uplink subframe to a downlink subframe, generating a second guard period, where the second guard period overlaps the uplink subframe or the downlink subframe, and that the terminal does not process any signal in the second guard period is defined, and therefore uncertainty of a terminal behavior during an uplink-to-downlink switching process of the terminal is avoided. By defining new terminal behaviors, the embodiments of the present invention can ensure that a network and the terminal can normally transmit and receive data.