A new low-complex interference cancellation scheme for WCDMA indoor repeaters

A new low-complex interference cancellation scheme for WCDMA indoor repeaters is presented in this paper. The real time interference cancellation performance of an indoor repeater depends on its computational complexity. In order to reduce the complexity of interference cancellation repeaters, computationally efficient interpolated filters are used as an input filter for frequency band selection and an output filter for spectrum mask control. Interpolation is applied to the implementation of an adaptive filter that performs interference cancellation under indoor channel environments. This allows the adaptive filter to calculate fewer filter taps and only uses them to estimate the feedback signal. For additional complexity reduction, a single common image rejection filter is designed to be shared among interpolated filters. The proposed scheme reduces the complexity of the conventional interference cancellation repeater by half without deterioration of the interference cancellation performance of the repeater.