BWA Base Station Interference Mitigation for MSS Satellites

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Solution Overview

Problem

Interference from terrestrial Broadband Wireless Access (BWA) base stations to Mobile Satellite Service (MSS) satellites is a significant issue due to shared radio spectrum usage, leading to signal degradation and communication disruptions.

Innovation Solution

Implementing geographically clustered BWA nulling with feedback loops to mitigate interference by refraining from assigning specific frequencies and reducing transmit power in base station subsectors, and using active antenna patterns to select optimal subsectors based on down tilt angles and directions relative to the MSS satellite, while monitoring and identifying interference-free frequency bands for MSS communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If BWA base stations use high transmit power to improve terrestrial communication coverage, then BWA system performance is improved, but interference to MSS satellite receivers increases

Engineering Contradiction:

ImproveBWA transmit powerVSAvoidInterference to MSS satellite

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by implementing geographically clustered nulling where different base station subsectors are assigned different nulling patterns based on their specific geographic location and orientation relative to the MSS satellite. This allows each subsector to have tailored interference mitigation characteristics while maintaining overall system performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the BWA base station coverage area into multiple subsectors, each with independently controlled transmit power and nulling patterns. This segmentation allows selective power reduction in directions that would cause satellite interference while maintaining full power in other directions for terrestrial communication.

Inventive Principle:

Principle #1Segmentation

2Productivity

If frequency spectrum is shared between BWA and MSS systems to improve spectral efficiency, then resource utilization is improved, but signal degradation and communication disruptions occur

Engineering Contradiction:

ImproveSpectral efficiencyVSAvoidCommunication reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the MSS satellite monitors interference levels from BWA base stations and provides feedback information to the BWA network. This feedback enables dynamic adjustment of BWA transmit power and resource allocation to maintain both spectral efficiency and communication reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent employs dynamic resource allocation and power control in the BWA system, where transmit power and frequency assignment are adjusted in real-time based on satellite position, interference conditions, and traffic demands. This allows the system to adaptively balance spectral efficiency and communication reliability.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If geographically clustered BWA nulling is implemented to reduce interference to MSS, then satellite interference is reduced, but BWA system complexity increases

Engineering Contradiction:

ImproveSatellite interference levelVSAvoidBase station control complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing nulling patterns for different base station subsectors based on their geographic locations and orientations. These pre-computed patterns are then applied during operation without requiring complex real-time calculations, thereby reducing interference while limiting complexity increase.

Inventive Principle:

Principle #10Preliminary action

4Object-affected harmful factors

If transmit power is reduced in base station subsectors to protect MSS satellite, then interference threshold is maintained, but BWA coverage area is reduced

Engineering Contradiction:

ImproveInterference threshold complianceVSAvoidBWA coverage area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent maintains BWA coverage by applying local quality differentials across subsectors - full power transmission in directions away from the satellite and reduced power only in subsectors that would cause interference. This preserves overall coverage area while meeting interference thresholds.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11677446B2Interference mitigation technique for a MSS system from an inverted terrestrial frequency BWA reuse

Publication Date: 2023.06.13 TELCOM VENTURES LLC

AI summary

Methods of mitigating interference to a Mobile Satellite Service (MSS) satellite from terrestrial Broadband Wireless Access (BWA) base stations are provided. A method includes receiving, at the terrestrial BWA base station, a pilot signal on a satellite downlink frequency, and adjusting terrestrial BWA communication on a satellite uplink frequency that corresponds to the satellite downlink frequency, responsive to the pilot signal.