Guardband Determination via Filter Roll-Off

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Solution Overview

Problem

The existing methods for determining guardbands in wireless communication systems result in unnecessarily large guardbands due to improved filter roll-offs, leading to underutilization of RF spectrum and artificial congestion, as they do not efficiently adapt to varying filter types and roll-offs in mobile devices and base stations.

Innovation Solution

A method and system that determine guardbands based on the roll-off or type of filters in both mobile devices and base stations, allowing for the selection of subcarriers that optimize channel usage by adjusting guardbands dynamically according to the specific filter characteristics of each device, thereby reducing unnecessary guardband sizes and improving spectrum utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If filters with poor roll-off are used, then device complexity is reduced, but adjacent channel interference increases requiring larger guardbands

Engineering Contradiction:
Improvefilter complexityVSAvoidadjacent channel interference
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically changes the guardband parameter based on the actual filter roll-off characteristics of each device. Instead of using a fixed conservative guardband size for all devices, the network determines the appropriate guardband width by measuring or receiving information about each device's filter performance, thereby optimizing the trade-off between spectrum utilization and interference protection.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If large fixed guardbands are used, then adjacent channel interference is prevented, but RF spectrum utilization decreases

Engineering Contradiction:
Improveadjacent channel interference protectionVSAvoidspectrum utilization
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The guardband configuration transitions from a static fixed value to a dynamic adaptive parameter. The system continuously adjusts guardband sizes based on real-time device filter characteristics, allowing the network to optimize spectrum allocation for each device individually while maintaining adequate protection against adjacent channel interference.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The guardband width parameter is changed dynamically according to each device's filter roll-off characteristics. Devices with sharper filter roll-offs receive smaller guardbands, while devices with poorer roll-off receive larger guardbands, optimizing both interference protection and spectrum efficiency.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If device-specific guardbands are implemented, then spectrum utilization improves, but system complexity increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system implements a feedback mechanism where devices provide information about their filter characteristics (such as roll-off measurements or filter type identifiers) to the network. The network uses this feedback to determine appropriate guardband configurations for each device, enabling adaptive spectrum allocation without requiring complex centralized control or coordination between devices.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3053406B1Filter-based guardband determination and subcarrier selection
Publication Date: 2020.04.29 T MOBILE US INC
  • EP3053406B1 patent drawingFigure 1
  • EP3053406B1 patent drawingFigure 2
  • EP3053406B1 patent drawingFigure 3

AI summary

Techniques for determining a guardband for a frequency channel based at least in part on a roll-off of a filter or a type of a filter are described herein. The filter may be a filter of a base station and the frequency channel may be used for transmissions from the base station to a mobile device. Alternatively, the filter may be a filter of a mobile device and the frequency channel may be used for transmissions from the mobile device to the base station. Further, because different filters of different mobile devices may have different roll-offs or types of filters, different guardbands may be determined for different mobile devices communicating over a same frequency channel. Upon determining the guardband, a base station may select a subcarrier based at least in part on the determined guardband.