Feedback phase-shift compensation for adaptive interference cancellers

An algorithm typically used for adaptive co-site interference cancellers (for frequency-hopping spread-spectrum communications systems) is the least-mean-square error (LMS) algorithm. As adaptive cancellation moves into L-band and S-band, feedback system stability becomes a critical issue for co-site interference cancellers using the LMS algorithm. The authors present a technique for compensating the high-frequency feedback path phase shifts leading to instability with an additional complex weight multiplication at baseband. Simulation and experimental results confirm the effectiveness of the technique