Complementary RF Sub-band Filters for Access Point Interference

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Solution Overview

Problem

The proximity of Wi-Fi and IEEE 802.15.4 radio transceivers in an access point leads to interference, causing the IEEE 802.15.4 radio to miss beacons during Wi-Fi transmissions, which hampers real-time asset tracking and locating capabilities.

Innovation Solution

The implementation of complementary radio frequency (RF) sub-band filters in the access point allows for simultaneous transmission by the Wi-Fi transceiver and reception by the IEEE 802.15.4 transceiver, using switchable filters to attenuate interference and enable continuous asset tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If Wi-Fi and IEEE 802.15.4 radio transceivers are placed in close proximity in an access point, then device integration and space utilization are improved, but interference between the two transceivers increases causing the IEEE 802.15.4 radio to miss beacons during Wi-Fi transmissions

Engineering Contradiction:
Improvedevice integrationVSAvoidinterference
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The radio frequency spectrum is segmented into different sub-bands using complementary filters. The Wi-Fi transceiver operates on specific frequency sub-bands while the IEEE 802.15.4 transceiver operates on complementary sub-bands, allowing both to coexist in close proximity without mutual interference. This spectral segmentation enables simultaneous operation by dividing the frequency domain into non-overlapping segments for each transceiver type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different frequency sub-bands are assigned to different transceivers based on their specific operational requirements. The Wi-Fi transceiver receives dedicated frequency sub-bands optimized for its higher bandwidth requirements, while the IEEE 802.15.4 transceiver receives complementary sub-bands suitable for its lower bandwidth but more sensitivity-critical operations. This localized frequency allocation ensures each transceiver operates in its optimal spectral region.

Inventive Principle:
Principle #3Local quality

2Productivity

If the IEEE 802.15.4 radio transceiver operates simultaneously with the Wi-Fi transceiver, then real-time asset tracking capability is improved, but signal interference increases causing beacon detection failures

Engineering Contradiction:
Improvereal-time asset tracking capabilityVSAvoidbeacon detection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The available radio frequency spectrum is divided into complementary sub-bands that are allocated to Wi-Fi and IEEE 802.15.4 transceivers respectively. This segmentation allows both transceivers to operate simultaneously without their signals interfering with each other, enabling continuous beacon detection for asset tracking while maintaining Wi-Fi communications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Complementary filters act as intermediary components between the two transceivers and the shared antenna system. These filters mediate the frequency domain, allowing each transceiver to access only its designated sub-bands while blocking interference from the other transceiver, thus enabling reliable simultaneous operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If complementary RF sub-band filters are implemented to reduce interference, then simultaneous transmission and reception is enabled, but device complexity increases

Engineering Contradiction:
Improvesimultaneous transmission and reception capabilityVSAvoidfilter implementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The complementary filter system serves multiple functions simultaneously: it enables frequency separation for interference reduction, allows simultaneous operation of both transceivers, and provides a unified solution for both transmission and reception paths. This multi-functionality justifies the added complexity by delivering comprehensive interference management across all operational modes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The filter banks for Wi-Fi and IEEE 802.15.4 transceivers are merged into a unified complementary filtering system that manages both transceivers' frequency allocations. By combining the filtering functions and sharing the infrastructure, the overall system complexity is reduced compared to implementing separate independent filtering systems for each transceiver.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables the access point to perform simultaneous Wi-Fi transmission and IEEE 802.15.4 reception, improving asset tracking accuracy and reliability by reducing interference, allowing for real-time and constant tracking of assets.

Implementation Method 1

a first RF sub-band filter on a first radio transceiver of an access point and a second RF sub-band filter, complementary to the first RF sub-band filter, on a second radio transceiver of the access point

Methodology Applied
Scientific EffectFilter (electronic): Filter (electronic)

Implementation Method 2

using switchable filters to attenuate interference

Methodology Applied
Scientific EffectAttenuation: Absorption (EM radiation)

Data Source

PatentEP3547792B1Transceiver filters
Publication Date: 2021.11.10 HEWLETT PACKARD ENTERPRISE DEV LP
  • EP3547792B1 patent drawingFigure 1A
  • EP3547792B1 patent drawingFigure 1B
  • EP3547792B1 patent drawingFigure 2

AI summary

An example may include access point, comprising: a processing resource; a first radio transceiver; a first radio frequency (RF) sub-band filter on the first radio transceiver; a second radio transceiver; a second RF sub-band filter, complementary to the first RF sub-band filter, on the second radio transceiver; and instructions executable by the processing resource to enable and disable the first RF sub-band filter and the second RF sub-band filter based on a network metric.