According to a first broad aspect of the present invention, there is provided a novel communication system having a forward link comprising: at least one base station which transmits multiple radio frequency (RF) signals; and a mobile station, the mobile station including: a receiver for receiving the RF signals; means for converting the RF signal to an intermediate frequency (IF) signal; means (704) for sampling the IF signal to generate a digital signal, the digital signal having a data component; means (712) for canceling co-channel and or cross-channel interference in the digital signal by projecting the IF signal into a subspace orthogonal to a subspace of the interference component and multiplying this projection with the digital signal; and means (710) for acquisition and tracking of the digital signal.

Interference cancellation in a signal

The method and apparatus of the present invention is directed to architectures for signal processing, such as for performing analog-to-digital and digital-to-analog conversions, in which the source signal is decomposed into subband signals by an analysis filter, processed, and the processed subband signals combined to form a reconstructed signal that is representative of the source signal.

Method and apparatus for acquiring wide-band pseudorandom noise encoded waveforms

An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.

Advanced Signal Processors for Interference Cancellation in Baseband Receivers

The present invention is directed to signal cancellation in spread spectrum communication systems (100). In particular, the present invention provides method and apparatus (120, 128 and 132) for selectively canceling interfering signals, even where symbols to be canceled do not align with symbols associated with a desired signal path. Furthermore, the interference cancellation provided by embodiments of the present invention is capable of functioning to remove interference associated with channels utilizing a symbol length that is different than the symbol length of a desired signal path. In accordance with a further embodiment of the present invention, method and apparatus for efficiently calculating projections to enable signal cancellation are provided.

Method and apparatus for interference suppression with efficient matrix inversion in a DS-CDMA system

The architecture of the present invention is premised upon an algorithm involving integration of oblique correlators and RAKE filtering to null interference from other spread spectrum signals. The oblique correlator is, of course, based on the non-orthogonal projections that are optimum for nulling structured signals such as spread spectrum signals. RAKE filtering is used to rapidly steer the beam of the multi-antenna system and to mitigate the effects of multipath.

Rake receiver for spread spectrum signal demodulation

A multi-stage decimation filter is described which consists of comb filters and a single-stage finite impulse response (FIR) filter. A multi-rate comb filter structure is used to reduce the data path width. A multi-stage interpolation filter consists of a half-band filter and a short FIR filter. The short FIR filter is designed with a nonlinear phase to realize an overall constant group delay-signal path. The coefficients of the FIR filters are optimally quantized to canonical-signed-digit form to realize multiplier-free (shift-and-add) filter implementations.

A. Krone

Papers

Digital filters for high performance audio delta-sigma analog-to-digital and digital-to-analog conversions