OFDM Interference Region Identification via Image Processing

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Solution Overview

Problem

In OFDM wireless communication systems, existing methods for estimating interference are limited by intermittent and varying interferer signals, leading to reduced accuracy and sensitivity to changing interference profiles, especially when only a single resource block is used for estimation.

Innovation Solution

The method involves processing interference measures from multiple time-frequency positions as a two-dimensional image, applying image processing algorithms like edge detection, segmentation, and clustering to identify regions with related interference parameters, and performing interference parameter estimation over these identified regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If interference parameter estimation is performed using data from a single resource block, then the estimation avoids problems from adjacent resource blocks with different interferer profiles, but the estimation accuracy is limited due to insufficient sample size

Engineering Contradiction:

Improveinterference parameter estimation accuracyVSAvoidnumber of estimation samples

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the time-frequency resource block into multiple sub-regions based on interference characteristics. By dividing the resource block and analyzing each segment separately, the system can identify regions with consistent interferer profiles and accumulate sufficient samples within each segment, thereby improving estimation accuracy without being contaminated by adjacent regions with different interference characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from analyzing interference in a single resource block to examining interference patterns across multiple resource blocks in the time-frequency domain. By utilizing the two-dimensional structure (time and frequency dimensions) of resource blocks and identifying correlated interference regions across these dimensions, the system accumulates more estimation samples while maintaining profile consistency through correlation-based selection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If interference parameter estimation uses multiple adjacent resource blocks, then more estimation samples are available, but accuracy degrades when interferer profiles vary between blocks

Engineering Contradiction:

Improvenumber of estimation samplesVSAvoidinterference parameter estimation accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies local quality by identifying and selecting specific sub-regions within resource blocks that exhibit consistent interferer profiles. Rather than uniformly processing entire resource blocks, the system locally identifies regions with matching interference characteristics and concentrates estimation samples from these localized areas, ensuring profile consistency while accumulating sufficient samples.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the approach from fixed resource block boundaries to dynamic region identification based on interference correlation parameters. By introducing correlation thresholds and similarity metrics as changeable parameters, the system adaptively determines which regions across multiple resource blocks should be grouped together for estimation, optimizing both sample quantity and profile consistency.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If interference estimation is performed in the presence of random thermal noise, then the system can operate in realistic conditions, but sufficient estimation samples are required to minimize noise effects

Engineering Contradiction:

Improveoperation in realistic noisy conditionsVSAvoidnumber of estimation samples

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and separates the interference signal from the combined noise-interference mixture by identifying regions with consistent interferer profiles across multiple resource blocks. By concentrating estimation samples from correlated regions and applying joint processing, the system extracts the interference component more effectively from thermal noise, reducing the minimum sample requirement compared to independent estimation in each block.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS8711769B2Interferer region identification using image processing

Publication Date: 2014.04.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Demodulation and interference parameter estimation in an OFDM receiver is improved by identifying regions, in a two-dimensional array of time-frequency transmission positions, having related interference parameters, such as resulting from the same pre-coding scheme, transmission rank, transmitting antennas, and the like. An interference measure is estimated for each of a plurality of time-frequency positions. The interference measures are analyzed by considering them as pixels, or picture elements, in a two-dimensional image, and applying image processing algorithms to identify the regions having related interference parameters. The image processing algorithms may include operations such as edge detection, segmentation, and/or clustering. The receiver may perform interference suppression or cancellation such as interference rejection combining of data extracted from signals received within an identified time-frequency region having related interference parameters.