What is RFSIC Radio Frequency Self Interference Cancelation

Radio Frequency Self Interference Cancellation (RFSIC) is a signal processing technique used to mitigate self-interference in radio frequency (RF) systems. Let’s dive into the technical details:

1. Self-Interference and the Problem:
   • Self-interference occurs when a transmitting antenna of a radio system interferes with its own receiving antenna.
   • This interference leads to signal degradation and performance limitations, especially in scenarios where simultaneous transmission and reception are required.
2. Basic Principle of RFSIC:
   • The fundamental idea behind RFSIC is to rebuild a copy of the RF self-interference signal using dedicated methods.
   • This rebuilt signal is then subtracted from the received signal, effectively canceling out the strong self-interference component.
   • By doing so, the system can achieve simultaneous transmission and reception on the same channel or frequency band.
3. Challenges and Techniques:
   • Canceling out the transmit signal at the receiver is not straightforward due to several factors:
     • Signal Variability: The received signal is subject to varying delays, leakage, local reflections, and non-linearities introduced by transmitter components.
     • Real-Time Changes: The solution must adapt to real-time changes caused by temperature variations, vibrations, and environmental motion.
   • Techniques for self-interference cancellation include:
     • Model-Based Cancellation: Creating an accurate model of the transmit signal and generating a cancellation signal to subtract from the received signal.
     • Precise Cancellation: Achieving the required cancellation depth (typically around 110 dB for Wi-Fi and cellular applications) based on the transmit signal power and expected signal-to-noise ratio (SNR).
4. Applications:
   • RFSIC finds applications in various domains:
     • Mobile Networks: Enhancing spectral efficiency and capacity.
     • Unlicensed Bands: Enabling full-duplex communication.
     • Cable TV: Improving performance in cable systems.
     • Mesh Networks: Supporting simultaneous communication.
     • Military and Public Safety: Enhancing communication reliability.