Analysis on Delay Arrangement of Analog Self-Interference Cancellation for Full-Duplex

Analog self-interference(SI) cancellation in full-duplex systems can be implemented with either fixed or adjustable delay arrangement. In this paper, the theoretical residual SI power in multi-tap analog SI cancellation with arbitrary time delay arrangement for each tap is derived, and the cancellation performance with fixed and optimal adjustable delay arrangement are compared by simulations. The influence of the bandwidth, the carrier frequency, the number of taps and the maximum delay of the SI channel on the cancellation performance are investigated. In consideration of the complexity of the optimal method, a novel algorithm for adjustable delay arrangement is proposed based on the cross-correlation of the reference signal and the SI signal.