Receiver Notch Filter Configuration for Narrowband Interference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Radio communication systems face challenges in mitigating narrowband interference, particularly in scenarios where limited spectrum is shared between different radio access technologies like GSM and WCDMA, leading to strong interference and reduced bandwidth efficiency.

Innovation Solution

A method and system for configuring a Notch filter in a radio communication receiver that reduces computational complexity by retrieving a fraction of stored filter coefficients, normalizing them, and transforming their position to effectively filter out specific frequencies, thereby enhancing Narrowband Interference Rejection (NBIR) capabilities and enabling efficient co-deployment of multiple Radio Access Technologies (RATs) in limited spectrum scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional NBIR filtering is implemented to remove narrowband interference, then interference rejection capability is improved, but computational complexity and processing overhead increase

Engineering Contradiction:
Improvenarrowband interference rejectionVSAvoidcomputational complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The filter coefficient set is segmented into two parts: a small subset of coefficients that are retrieved and processed, and the remaining coefficients that are set to default values. This segmentation allows the system to achieve effective interference filtering while minimizing computational overhead by only processing the essential coefficient subset.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of retrieving and processing all filter coefficients, the method applies partial action by retrieving only a fraction of the coefficients needed for effective NBIR. This partial processing approach maintains sufficient filtering performance while dramatically reducing computational complexity.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If multiple Radio Access Technologies are deployed in limited spectrum, then spectrum utilization is improved, but interference between technologies increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidinterference between RATs
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The Notch filter acts as an intermediary mechanism between different Radio Access Technologies sharing the same spectrum. By selectively attenuating specific frequency components that cause interference between GSM and WCDMA, the filter enables coexistence of multiple RATs without significantly impacting overall spectrum utilization.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If deep Notch filtering is applied to remove strong interference, then interference rejection is improved, but desired signal spectrum may be affected

Engineering Contradiction:
Improveinterference removal effectivenessVSAvoidsignal integrity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The filter configuration applies local quality by creating a deep Notch only at the specific interference frequency while maintaining passband characteristics elsewhere. This localized filtering approach ensures strong interference removal at the target frequency while preserving the integrity of the desired signal spectrum in adjacent frequencies.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3472940B1Radio communication receiver and method for configuring a notch filter of the radio communication receiver
Publication Date: 2020.04.08 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3472940B1 patent drawingFigure 1a~1b
  • EP3472940B1 patent drawingFigure 1c~1d
  • EP3472940B1 patent drawingFigure 2a

AI summary

A radio communication receiver and a method performed by the radio communication receiver for configuring a Notch filter of the radio communication receiver are disclosed. The method (100) comprises retrieving (120) stored and previously determined filter coefficients from a set of filter coefficients, where the retrieved filter coefficients constitute a fraction of the total number of filter coefficients; and setting (130) the rest of the filter coefficients to one. The method (100) further comprises normalising (140) the retrieved filter coefficients; and transforming (160) the filter coefficients such that the Notch position ends up at the one or more frequencies to be filtered out.