Variable Time-Delay Channel Matching for Cosite Interference Cancellation

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Solution Overview

Problem

Existing radio communication systems face interference issues due to unwanted signals from collocated transmitters, which degrade receiver performance and are challenging to address with current adaptive interference cancellation methods, especially in dynamic environments where manual adjustments are required.

Innovation Solution

A cosite interference cancellation system using a time-delay based control architecture dynamically adjusts the delay match between signal paths to maximize autocorrelation and minimize correlated error feedback, continuously varying the time delay to optimize interference cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manual adjustment methods are used for interference cancellation, then system complexity is reduced, but adaptability to dynamic environments deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidadaptability to dynamic environments

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptation by continuously monitoring the interference environment and automatically adjusting cancellation parameters in real-time. The system transitions from static manual configuration to dynamic automatic adjustment, enabling the interference cancellation system to adapt to changing propagation conditions, moving platform positions, and varying interference characteristics without requiring manual reconfiguration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs self-adjustment by automatically detecting interference signals, calculating optimal cancellation parameters, and applying corrections without external intervention. The adaptive algorithm autonomously tracks interference variations and modifies cancellation weights and delays, enabling the system to serve itself in dynamic environments rather than requiring continuous manual tuning.

Inventive Principle:

Principle #25Self-service

2Device complexity

If fixed time delay is used in interference cancellation, then device complexity is reduced, but measurement precision of path length match deteriorates

Engineering Contradiction:

Improvedevice complexityVSAvoidpath length match precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent dynamically changes the time delay parameter based on measured path length differences between direct and coupled signal paths. Instead of using a fixed delay value, the system continuously adjusts the delay parameter to match the actual propagation path length, thereby achieving precise path length matching that adapts to varying environmental conditions and maintains optimal interference cancellation performance.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If adaptive interference cancellation is implemented, then signal rejection is improved, but device complexity increases

Engineering Contradiction:

Improvesignal rejectionVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system employs feedback mechanisms where the output of the interference cancellation process is monitored and used to continuously refine the cancellation parameters. The adaptive algorithm uses feedback from the residual interference signal to adjust weights, phases, and delays, creating a closed-loop system that automatically optimizes signal rejection while managing complexity through efficient feedback processing.

Inventive Principle:

Principle #23Feedback

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 approach significantly improves signal rejection and maintains communication quality by continuously adapting to changing environments, reducing the impact of interference between collocated transceivers.

Implementation Method 1

maximize the autocorrelation between a transmitted reference signal and a continuously varied time-delayed version of the transmitted reference signal

Methodology Applied

Scientific EffectAutocorrelation:

Data Source

PatentUS8094764B2Variable time delay control structure for channel matching

Publication Date: 2012.01.10 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC

AI summary

A cosite interference cancellation system is provided for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. The cosite interference cancellation system and associated method advantageously provide improved signal rejection by continuously controlling (adjusting) a matching time delay to reduce cosite interference.