Hybrid Time-Domain/Frequency-Domain Self-Interference Cancellation for STAR Applications

This talk presents a multistage hybrid time-domain/frequency-domain architecture for wideband self-interference cancellation in simultaneous transmit and receive (STAR) applications. The system comprises two stages of RF-domain cancellation, with partitioning of technologies and architectures to optimize cancellation bandwidth, linearity, and system noise figure. The first stage of cancellation is a high-linearity hybrid time/frequency domain architecture utilizing passive delay lines, phase shifters, and tunable filters. Cancellation from the first stage relaxes the linearity requirements on the second stage, which uses a frequency-domain approach based on CMOS N-path filters. The combined stages of cancellation yield high self-interference suppression over a wide bandwidth, while maintaining high linearity and power handling for compatibility with high transmit powers.