Software Radio Frequency Interference Cancellation via Adaptive Filtering
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Solution Overview
Problem
Existing full-duplex RF communication systems face challenges in real-time operation due to complex hardware-based cancellation methods and inadequate interference cancellation, especially when using co-sited or coupled antennas, which result in inefficient bandwidth usage and high computational requirements.
Innovation Solution
A software-based adaptive filtering method that converts analog signals into digital, using a digital adaptive filter with a tap weight estimator to calculate tap weight values for a subset of data frames, allowing for real-time interference cancellation without frequency-, time-, or code-division multiplexing, and without hardware RF cancellers, by interpolating or repeating tap weight values to maintain low bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hardware RF cancellers are used for interference cancellation, then interference cancellation capability is improved, but device complexity increases and adequate canceling is not achieved
Solution Approach 1:
The patent replaces hardware-based RF cancellers with a software-based digital signal processing approach. The system uses analog-to-digital converters to transform RF signals into digital domain, where adaptive filtering algorithms perform interference cancellation. This substitution of mechanical/hardware systems with software/digital processing resolves the contradiction by achieving adequate canceling performance without the complexity of multiple hardware cancellation filters.
Solution Approach 2:
The patent changes the operating domain from analog RF domain to digital baseband domain. By converting signals to digital form and performing cancellation operations in the digital domain with adjustable tap weights, the system achieves flexible and adequate interference cancellation. The parameter changes include transitioning from fixed hardware filtering to adaptive digital filtering with dynamically adjustable coefficients.
2Object-affected harmful factors
If full-band cancellers are used to cancel transmission components, then interference cancellation is improved, but real-time operation cannot be achieved due to extensive computational requirements
Solution Approach 1:
The patent segments the computational workload by processing data in frames and calculating tap weight values for only a subset of frames. Instead of performing full computational processing on every incoming sample, the system divides the continuous signal stream into discrete frames and selectively processes representative subsets, enabling real-time operation while maintaining adequate cancellation performance.
Solution Approach 2:
The patent applies partial action by calculating tap weight values for only a subset of data frames rather than every frame. The system estimates or interpolates tap weights for intermediate frames based on calculated values from subset frames, achieving acceptable cancellation performance with reduced computational effort that enables real-time operation.
3Object-affected harmful factors
If multiple cancellation filters are used in hardware-based canceling systems, then interference cancellation is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent merges multiple hardware cancellation filters into a single software-based adaptive filtering system. Instead of implementing separate physical filters for different frequency bands or signal paths, the system uses a unified digital signal processing architecture where a single adaptive filter with adjustable tap weights performs cancellation across the entire bandwidth, significantly reducing device complexity.
Solution Approach 2:
The patent creates a universal software-based cancellation system that can handle multiple signal types, frequency bands, and interference scenarios through a single adaptive filtering framework. The same digital signal processing architecture and algorithm can be configured for different applications by adjusting parameters and tap weights, eliminating the need for dedicated hardware filters for each specific case.
Data Source
AI summary
A full-duplex RF communication system and corresponding methods use digital adaptive filters for interference cancellation. As provided, the techniques allow full-duplex radio frequency communication without frequency-, time-, or code-division multiplexing and without the use of hardware RF cancellers, in real-time. Such techniques may be useful for wireless communication, such a cellular communication, radio communication, broadcasting, short-range point-to-point communication, wireless sensor networks, and wireless computer networks.