SGLTE Coupling De-sense Reduction via Band Stop Filtering

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Solution Overview

Problem

SGLTE mobile terminals experience severe coupling de-sense due to interference between GSM and LTE bands, particularly when GSM and TDD/LTE bands coexist, leading to decreased audio quality and increased data error rates.

Innovation Solution

Implementing a band stop filter in the GSM transmission path to filter out the LTE frequency band and a GSM reception filter to isolate GSM signals from other frequency bands, using piezoelectric crystal oscillator materials like ceramic, lithium niobate, and quartz, to minimize transmission loss and attenuate interfering frequencies by at least 20 dB.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If GSM and LTE bands coexist in SGLTE mode, then dual communication functionality is achieved, but coupling de-sense and signal interference occur

Engineering Contradiction:

Improvedual communication functionalityVSAvoidsignal quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the frequency spectrum by implementing separate filtering paths for GSM and LTE bands. A band stop filter is inserted in the GSM transmission path to segment and remove LTE frequency components, while a GSM reception filter segments and removes non-GSM frequency components. This segmentation allows dual communication functionality while preventing frequency band interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts harmful frequency components from the signal paths. The band stop filter extracts LTE frequency bands from the GSM transmission path, and the GSM reception filter extracts non-GSM frequency bands from the received signal. This extraction eliminates the coupling de-sense effect while preserving the desired communication functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

2Object-affected harmful factors

If band stop filter is added to GSM transmission path, then LTE interference is attenuated, but device complexity increases

Engineering Contradiction:

ImproveLTE interferenceVSAvoidfilter structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces band stop filters as intermediary components in the signal paths. The band stop filter acts as a mediator between the GSM transmission path and LTE frequency bands, selectively removing interfering frequencies without affecting the overall system architecture. This intermediary approach attenuates LTE interference while maintaining relatively simple device structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If separation between DCS and B39 antennas is increased, then coupling de-sense is reduced, but device size increases

Engineering Contradiction:

Improvecoupling sensitivityVSAvoidantenna separation distance

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanical solution of increasing antenna separation distance with an electronic filtering solution. Instead of physically separating antennas to reduce coupling de-sense, the patent uses band stop filters and reception filters to electronically eliminate frequency band interference. This substitution maintains compact device size while achieving the desired coupling sensitivity improvement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Significantly reduces SGLTE coupling de-sense by isolating GSM signals from LTE interference, maintaining low GSM transmission loss, and enhancing overall sensitivity by filtering out unwanted frequency bands, thereby improving signal quality and reducing errors.

Implementation Method 1

a band stop filter is provided in the GSM transmission path to filter out the LTE frequency band in the signal to be transmitted on the GSM signal transmission end

Methodology Applied

Scientific EffectFilter (electronic): Filter (electronic)

Implementation Method 2

the band stop filter is composed of a piezoelectric crystal oscillator material

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

filtering out all frequency bands other than a GSM frequency band in a received signal on a GSM signal reception end

Methodology Applied

Scientific EffectFilter (electronic): Filter (electronic)

Data Source

PatentUS11522569B2Method for reducing SGLTE coupling de-sense and mobile terminal

Publication Date: 2022.12.06 HUIZHOU TCL MOBILE COMM CO LTD

AI summary

Disclosed in the present application are a method for reducing SGLTE coupling de-sense and a mobile terminal, the method including: filtering out an LTE network frequency band in a signal transmitted by a signal transmission end of a GSM; and filtering out a network frequency band in a signal of a signal reception end accessing the GSM other than a GSM network frequency band. Employing the present application may eliminate mutual interference between a GSM signal and an LTE signal due to the GSM network frequency band and the LTE network frequency band getting too close to each other, which greatly alleviates SGLTE mobile terminal coupling de-sense situation.