HF Base Station Sounding Scheduling for Interference Mitigation

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Solution Overview

Problem

High frequency (HF) cellular systems experience significant call blocking due to terminal sounding interference, leading to probabilities ranging from 28% to 60% during the day, with sounding interference accounting for up to 18% of call blocking failures.

Innovation Solution

Implement a controller to manage base station sounding operations by ensuring only one base station sounds at a time on unique frequencies, using a random or specified order, and utilizing wideband auxiliary receivers to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If terminal sounding operations are performed in HF cellular systems, then channel quality measurement is enabled, but sounding interference causes call blocking probability to increase to 28-60%

Engineering Contradiction:

Improvechannel quality measurementVSAvoidcall blocking probability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the traditional sounding approach by having base stations perform sounding transmissions instead of terminals. This reversal eliminates the harmful interference caused by terminal sounding while maintaining the necessary channel quality measurement capability, reducing call blocking probability from 28-60% to under 1%.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent segments the sounding operation into controlled time intervals and assigns different base stations to different frequencies sequentially. This segmentation prevents simultaneous sounding transmissions that would cause interference, allowing channel quality measurement to proceed without increasing call blocking probability.

Inventive Principle:

Principle #1Segmentation

2Productivity

If multiple base stations perform sounding transmissions simultaneously on the same frequency, then sounding operations are efficient, but interference between base stations increases call blocking

Engineering Contradiction:

Improvesounding operation efficiencyVSAvoidsounding interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic sounding transmissions where base stations transmit sounding signals in alternating time intervals rather than simultaneously. Each base station is assigned specific time slots for sounding, creating a periodic pattern that eliminates interference while maintaining operational efficiency through systematic rotation of sounding responsibilities.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent resolves the conflict by adding a time dimension to the sounding operation. Instead of allowing multiple base stations to sound simultaneously on the same frequency (spatial conflict), the system schedules them in different time intervals, transforming the problem from a spatial to a temporal solution that eliminates interference while preserving efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20260045967A1Mitigation of sounding interference in high frequency cellular systems

Publication Date: 2026.02.12 ROCKWELL COLLINS INC

AI summary

A high frequency (HF) cellular system includes base stations and HF terminals that initiate calls in the HF cellular system. The base stations perform sounding operations of transmitting sounding transmissions from the base stations to the HF terminals. A controller within the HF cellular system manages the sounding operations by having the base stations sound at different time intervals at specified frequencies.