Abstract: The present invention relates to the efficient realization of a time variant multi-rate FIR filter cascaded with a time invariant FIR filter. Preferably, the time invariant FIR filter response provides filtering based on channel estimates and the time variant FIR filter provides filtering to effectively implement spreading and scrambling with appropriate coding. The realization of the combined filters is accomplished by transforming the pair of filters into a single “combined” polyphase filter with coefficients that are time variant in a specific manner. The invention provides for pre-calculating the coefficients of the combined filter; a memory storage and addressing scheme for the resulting coefficients that ensures that the combined filter behaves like the original pair of filters; and overall polyphase decomposition of the resulting filter to significantly reduce the computational complexity as compared to the requirements of the original pair of filters.

Abstract: The present invention provides for improved parallel interference cancellation. An input signal composed of multiple user signals is processed over a select time duration. The input signal is separated into individual signals corresponding to each of the multiple users and demodulated to recover symbols for each of the individual signals. The recovered symbols are processed based on the consistency of previous estimates of the given symbol to provide weighted symbol estimates. The respective weighted symbol estimates for each of the users are modulated with the appropriate coding and processed using channel estimates to create individual, regenerated signals. For each user, the regenerated signals for the other users are subtracted from the original input signal to form new individual signals. The new individual signals are each demodulated and reprocessed for multiple iterations. The output of the last iteration is used to form the final symbol decisions for each user signal.

Abstract: The present invention relates to the efficient realization of a time variant multi-rate FIR filter cascaded with a time invariant FIR filter. Preferably, the time invariant FIR filter response provides filtering based on channel estimates and the time variant FIR filter provides filtering to effectively implement spreading and scrambling with appropriate coding. The realization of the combined filters is accomplished by transforming the pair of filters into a single “combined” polyphase filter with coefficients that are time variant in a specific manner. The invention provides for pre-calculating the coefficients of the combined filter; a memory storage and addressing scheme for the resulting coefficients that ensures that the combined filter behaves like the original pair of filters; and overall polyphase decomposition of the resulting filter to significantly reduce the computational complexity as compared to the requirements of the original pair of filters.

Abstract: The present invention provides for improved parallel interference cancellation. An input signal composed of multiple user signals is processed over a select time duration. The input signal is separated into individual signals corresponding to each of the multiple users and demodulated to recover symbols for each of the individual signals. The recovered symbols are processed based on the consistency of previous estimates of the given symbol to provide weighted symbol estimates. The respective weighted symbol estimates for each of the users are modulated with the appropriate coding and processed using channel estimates to create individual, regenerated signals. For each user, the regenerated signals for the other users are subtracted from the original input signal to form new individual signals. The new individual signals are each demodulated and reprocessed for multiple iterations. The output of the last iteration is used to form the final symbol decisions for each user signal.