Dynamic Guard Band Adjustment for Adjacent Transceiver Coexistence

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Solution Overview

Problem

The challenge in wireless telecommunication systems is to enable efficient coexistence of multiple radio systems operating in close proximity using adjacent frequency bands, particularly in unlicensed bands, where interference from incumbent and future communication systems poses significant challenges due to limited spectrum and changing regulations.

Innovation Solution

The solution involves a communication device with a controller managing multiple transceivers, which operate in a frequency division multiplexing mode by dynamically adjusting band selective filters to create a guard band between adjacent frequency bands, ensuring minimal interference by optimizing the location of the guard band based on detected channel usage, thereby allowing concurrent operation without the need for a dedicated guard band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a guard band is introduced between adjacent frequency bands to reduce interference, then interference suppression is improved, but system resource utilization deteriorates due to the dedicated guard band occupying spectrum that could be used for data transmission

Engineering Contradiction:
Improveinterference suppressionVSAvoidsystem resource utilization
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies dynamics by making the filter characteristics adjustable and adaptive rather than fixed. The band selective filters can dynamically change their frequency response based on the operational state of adjacent transceivers, allowing the guard band to be created only when and where needed, thus optimizing both interference suppression and resource utilization

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by creating guard bands locally at specific frequency boundaries where interference occurs, rather than implementing a fixed guard band across the entire spectrum. The filter adjusts to provide interference suppression only at the necessary frequency boundaries while allowing full utilization of the remaining spectrum resources

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If time division multiplexing is used to enable coexistence of multiple systems, then interference between systems is reduced, but overall data rate deteriorates due to sequential operation rather than simultaneous operation

Engineering Contradiction:
Improveinterference reductionVSAvoidoverall data rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent enables simultaneous operation of multiple transceivers by using dynamically adjustable band selective filters that can adapt to the presence of adjacent systems. This allows frequency division multiplexing to work effectively without requiring time division, thereby maintaining high data rates while reducing interference through real-time filter adjustment

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If band selective filters are used to create a guard band dynamically, then interference mitigation is improved, but device complexity increases due to the need for adjustable filters and control mechanisms

Engineering Contradiction:
Improveinterference mitigationVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses feedback by having the controller detect the operational state of adjacent transceivers and adjust the filter characteristics accordingly. This feedback mechanism enables automatic adaptation to interference conditions, providing effective interference mitigation while keeping the control logic relatively simple and integrated into the existing transceiver architecture

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the quality of performance by minimizing interference and maximizing resource utilization, allowing various radio communication systems to coexist effectively while avoiding the wastage of system resources typically associated with traditional guard band usage.

Implementation Method 1

interference at the first transceiver caused by transmissions of the second transceiver is mitigated, at least in part, by means of filtering

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Implementation Method 2

the filter must ensure that the out-of-band (OOB) emissions of one system are sufficiently low enough to avoid causing an unacceptable degradation of the other system's ability to receive signals

Methodology Applied
Scientific EffectAttenuation: Absorption (EM radiation)

Data Source

PatentEP2502436B1Methods and apparatuses for coexistence of plural wireless communication transceivers in close proximity
Publication Date: 2017.02.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2502436B1 patent drawingFigure 1
  • EP2502436B1 patent drawingFigure 2
  • EP2502436B1 patent drawingFigure 3a~3b

AI summary

A communication device has a controller operatively connected to at least a first transceiver and a second transceiver, wherein the first transceiver receives signals on one or more channels within a first frequency band and the second transceiver transmits signals on one or more channels within a second frequency band, wherein the first and second frequency bands are adjacent one another so that each of the first and second frequency bands has an adjacent border and a nonadjacent border. Coexistence between the first and second transceivers is achieved by adjusting receive and/or transmit filters associated with the transceivers to create a guard band that is located more in the first frequency band if the second transceiver is using frequencies close to its adjacent border, and a guard band that is more in the second frequency band if the second transceiver is not using frequencies close to its adjacent border.