Full-Duplex Signal Reconstruction for Self-Interference Cancellation
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Solution Overview
Problem
Full duplex radio (FDR) systems face significant challenges in effectively canceling self-interference, which hinders the simultaneous transmission and reception of signals using the same resource, leading to interference issues such as intra-device self-interference, UE to UE inter-link interference, and BS to BS inter-link interference.
Innovation Solution
A method and apparatus for reconstructing desired signals in FDR systems, incorporating a digital self-interference cancellation unit, demodulator, modulator, attenuator, and operation unit to process digital signals, with an attenuation coefficient set to minimize mean square error, and additional components like deinterleavers, channel encoders, and equalizers to enhance signal recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex radio scheme is used to enable simultaneous transmission and reception, then communication efficiency is improved, but self-interference increases
Solution Approach 1:
The patent segments the self-interference cancellation process into multiple stages: analog cancellation before ADC and digital cancellation after ADC. This multi-stage approach divides the complex interference cancellation task into manageable parts, effectively reducing self-interference while maintaining full duplex operation
Solution Approach 2:
The patent introduces an intermediary reconstruction process where the transmitted signal is reconstructed through the same signal chain (modulator, attenuator, etc.) and used as a reference for cancellation. This intermediary signal serves as a mediator to accurately model and subtract the self-interference component from the received signal
2Power
If transmitted signal power is increased to improve communication range, then signal coverage is improved, but self-interference power increases
Solution Approach 1:
The patent converts the harmful high-power transmitted signal into a useful reference for cancellation. By reconstructing the transmitted signal through the same signal chain and using it to model the self-interference, the system transforms the problematic high-power transmission into a beneficial tool for identifying and removing the interference component
3Measurement precision
If digital signal processing is used to cancel self-interference, then cancellation accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent performs preliminary analog cancellation before ADC to reduce the magnitude of self-interference early in the signal chain. This preliminary action reduces the dynamic range requirements and computational burden for subsequent digital processing, achieving high cancellation accuracy with reduced complexity
Data Source
AI summary
The apparatus for reconstructing a desired signal using a full duplex radio (FDR) scheme includes: a digital self-interference cancellation unit configured to output a first digital signal; a demodulator configured to demodulate the first digital signal; a modulator configured to modulate the demodulated first digital signal; an attenuator configured to attenuate the modulated first digital signal by applying an attenuation coefficient to the modulated first digital signal; and an operation unit configured to receive the attenuated first digital signal and the first digital signal, and transmit a residual signal to the digital self-interference cancellation unit, wherein the residual signal is obtained by subtracting the attenuated first digital signal from the first digital signal.