  Self-interference cancellation plays a crucial role in achieving reliable
full-duplex communications. In general, it is essential to cancel the
self-interference signal below the thermal noise level, which necessitates
accurate reconstruction of the self-interference signal. In this paper, we
propose a high-precision channel estimation method specifically designed for
sub-noise self-interference cancellation. Exploiting the fact that all
transmitted symbols are known to their respective receivers, our method
utilizes all transmitted symbols for self-interference channel estimation.
Through analytical derivations and numerical simulations, we validate the
effectiveness of the proposed method. The results demonstrate the superior
performance of our approach in achieving sub-noise self-interference
cancellation.
