FDD-TDD Interference Reduction via Truncated Carrier Segmentation

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Solution Overview

Problem

Current communication systems face interference issues between frequency-division duplex (FDD) and time-division duplex (TDD) signals, particularly in LTE-A based systems, due to the coexistence of operators using different duplex modes within the same spectral allocation, leading to challenges in carrier aggregation and intersystem handover.

Innovation Solution

The system employs a processor and memory configuration to allocate a time-division duplex carrier with a truncated time duration for FDD downlink signals, allowing for coexistence without interference by muting complementary periods for device-to-device communication, thus enabling flexible spectrum usage and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If time-division duplex carrier is allocated for frequency-division duplex downlink signal, then carrier aggregation flexibility is improved, but interference with time-division duplex uplink signals occurs

Engineering Contradiction:

Improvecarrier aggregation flexibilityVSAvoidinterference with TDD uplink signals

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The time-division duplex carrier is segmented into two distinct time periods: a first time period allocated for frequency-division duplex downlink signals and a second time period allocated for time-division duplex uplink signals. This temporal segmentation allows both duplex modes to coexist on the same carrier without interference, resolving the contradiction between carrier aggregation flexibility and interference avoidance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic time period allocation where the base station can flexibly assign different time durations to FDD downlink and TDD uplink periods based on traffic conditions. This dynamic adjustment enables the system to adapt to varying communication needs while maintaining interference-free operation between the two duplex modes.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If truncated time duration is used for FDD downlink signal, then interference reduction is improved, but transmission time is reduced

Engineering Contradiction:

Improveinterference reductionVSAvoidtransmission time

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The transmission time is segmented into distinct non-overlapping intervals: the FDD downlink transmits during the first time period while the TDD uplink transmits during the second time period. This segmentation allows the FDD downlink to use a truncated time duration without compromising overall system throughput, as the TDD uplink utilizes its dedicated time slot without interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs periodic time-division multiplexing where FDD downlink and TDD uplink signals transmit in alternating time periods. This periodic action pattern ensures that each signal type receives adequate transmission time while avoiding interference, with the base station controlling the periodic switching between modes.

Inventive Principle:

Principle #19Periodic action

3Productivity

If frequency-division duplex and time-division duplex systems coexist in same spectrum, then spectrum utilization is improved, but system interference increases

Engineering Contradiction:

Improvespectrum utilizationVSAvoidsystem interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The shared spectrum is segmented into distinct time periods for different duplex modes. Within the same frequency band, the base station divides time such that FDD downlink signals transmit during specific intervals while TDD uplink signals transmit during other intervals. This temporal segmentation enables high spectrum utilization by allowing both modes to operate simultaneously in the frequency domain without mutual interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements dynamic time-division multiplexing that adapts to real-time traffic conditions. The base station dynamically adjusts the time allocation between FDD and TDD modes based on current communication demands, optimizing spectrum utilization while preventing interference. This dynamic control allows efficient use of shared spectrum resources.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9560635B2Apparatus and method to reduce interference between frequency-division duplex and time-division duplex signals in a communication system

Publication Date: 2017.01.31 RESMED INC

AI summary

An apparatus, method and system to reduce interference between frequency-division duplex and time-division duplex signals in a communication system. In one embodiment, an apparatus includes a processor (520) and memory (550) including computer program code. The memory (550) and the computer program code are configured to, with the processor (520), cause the apparatus to allocate a time-division duplex carrier for a frequency-division duplex downlink signal for communication with a communication element, and employ the time-division duplex carrier with a truncated time duration for the frequency-division duplex downlink signal.