Multi-Rate Digital Self-Interference Cancellation for Full-Duplex Transceivers
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Solution Overview
Problem
Full-duplex wireless communication systems face challenges with self-interference due to the simultaneous transmission and reception on the same channel, leading to performance limitations, especially in non-linear regimes, as existing digital self-interference cancellation methods are inadequate.
Innovation Solution
A system and method for multi-rate digital self-interference cancellation, incorporating a signal component generation system, multi-rate adaptive filter, and transform adaptor, which generates and combines weighted signal components to effectively cancel self-interference in full-duplex wireless communications systems, utilizing mathematical models like generalized memory polynomial models to account for non-linearities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional digital self-interference cancellation methods are used in full-duplex systems, then implementation complexity is reduced, but cancellation performance deteriorates especially in non-linear regimes
Solution Approach 1:
The patent segments the self-interference cancellation process into multiple independent modules: non-linear signal component generation, multi-rate adaptive filtering, and transform adaptation. Each module processes specific aspects of the interference cancellation, allowing complex non-linear compensation without proportionally increasing overall system complexity. The segmentation enables parallel processing and modular optimization.
Solution Approach 2:
The patent dynamically changes multiple parameters including sampling rates (multi-rate processing), transform configurations (FFT size, window functions), and adaptive filter coefficients. These parameter changes allow the system to adapt to varying operating conditions and maintain high cancellation performance across different power levels and signal conditions without requiring a completely different system architecture.
2Productivity
If full-duplex communication is implemented, then spectral efficiency is improved, but self-interference increases
Solution Approach 1:
The patent converts the harmful self-interference signal into a useful component for cancellation. By capturing the transmitted signal and processing it through non-linear models that mirror the actual interference generation process, the system creates an accurate replica of the self-interference that can then be subtracted from the received signal. This transforms the harmful interference into a beneficial cancellation reference.
Solution Approach 2:
The patent performs preliminary processing of the transmitted signal to pre-compensate for non-linearities before the signal causes interference. By applying non-linear signal component generation and adaptive filtering in advance, the system prepares the cancellation signal with the correct non-linear characteristics, enabling more effective interference removal when the signals combine at the receiver.
3Power
If high transmission power is used to expand power range, then system capability is improved, but self-interference and non-linearities increase
Solution Approach 1:
The patent implements dynamic adaptation of transform parameters and adaptive filter coefficients based on the current operating power level. The transform adaptor dynamically adjusts FFT sizes, window functions, and other parameters according to the signal conditions. This dynamic behavior allows the system to maintain optimal cancellation performance across the entire power range, from low to high transmission powers, by continuously adapting to the changing non-linear characteristics.
Data Source
AI summary
A system for multi-rate digital self-interference cancellation including a signal component generation system coupled to a digital transmit signal of a communication system that generates a set of signal components from the digital transmit signal; a multi-rate adaptive filter that transforms the set of signal components into a digital self-interference cancellation signal, according to a transform configuration, to form an interference-reduced receive signal; and a transform adaptor that dynamically sets the transform configuration in response to changes in the interference-reduced receive signal.