Comprehensive Analysis of Quantization Effects on Digital-Controlled Adaptive Self-Interference Cancellation System

A digital-controlled adaptive self-interference cancellation system with capabilities of high interference cancellation ratio and strong environmental applicability is presented. The key part - analog-to-digital converter (ADC) / digital-to-analog converter (DAC) quantization effect, is analysed comprehensively. Specially, the analytical relation between the quantization noise and the interference cancellation ratio is derived, which can provide important guidance for system implementation and performance optimization. The theoretical deductions are validated firstly by Simulink simulation and then by practical experimental measurements. Both the analysis and experiments show that the system stability and convergence property are not affected by ADC/DAC. The magnification of the conditioning circuit in front of the error-sampled ADC plays an important role in the cancellation ratio improvement. The practical space channel measurements presented an average interference cancellation ratio of 59 dB for the single-tone interference waveform and 50 dB for the amplitude-modulated (AM) interference waveform, rendering the system as a powerful tool for solving the in-band self-interference problem.