A scheme to decrease the taps'number for adaptive filter in an interference cancellation repeater for mobile communication systems

The feedback interference that comes into receiving antenna from the transmitting antenna has a bad effect on the normal work of the radio repeater. What's worse, serious feedback interference will incur feedback oscillation. The introduction of Adaptive Interference Cancellation (AIC) solves this problem effectively. When AIC is employed, the feedback time that feedback interference transmits between antennas is long, therefore, a large number of taps of the Adaptive Filter (AF) are needed to cancel feedback interference, this results in high-complex AIC design. Based on the analysis of the LMS adaptive algorithm and the correlation property of WCDMA signal, this paper proposes to decrease the number of taps through regulating the reference signal of AIC. The validity of the proposed scheme is confirmed by computer simulation that shows two schemes' performance on interference cancellation under the different taps' number of AF.