Time variant filter implementation

A transceiver comprising:

• a) receiving circuitry for receiving and downconverting a transmitted signal to provide a downconverted signal;
• and
• b) a baseband processor adapted to receive the downconverted signal and:
• i) calculate each filter coefficient for a combined time invariant finite impulse response (FIR) filter and time variant FIR filter;
• ii) store each filter coefficient in a memory array in addressable groups corresponding to a filtering period;
• and
• iii) filter data in the downconverted signal with the combined time invariant FIR filter and time variant FIR filter using a polyphase decomposition of the filter coefficients to create an output signal.
• a) receiving an input signal over a select period, the input signal including a plurality of user signals;
• b) for each user signal, subtracting individual regenerated signals corresponding to all other user signals from the input signal to create an individual signal;
• c) demodulating each individual signal to provide a corresponding demodulated individual signal;
• d) processing each demodulated individual signal to determine symbol estimates for each symbol included therein;
• and
• e) creating the individual regenerated signals from the symbol estimates using the calculating, storing and filter steps.

A system comprising:

• a) receiving circuitry for receiving and downconverting a transmitted signal to provide a downconverted signal;
• and
• b) a baseband processor adapted to receive the downconverted signal and:
• i) calculate each filter coefficient for a combined time invariant finite impulse response (FIR) filter and time variant FIR filter;
• ii) store each filter coefficient in a memory array in addressable groups corresponding to a filtering period;
• and
• iii) filter data in the downconverted signal with the combined time invariant FIR filter and time variant FIR filter using a polyphase decomposition of the filter coefficients to create an output signal.

A system for filtering a signal comprising:

• a) means for calculating each filter coefficient for a combined time invariant finite impulse response (FIR) filter and time variant FIR filter wherein the time invariant FIR filter response provides filtering based on a channel estimate and the time variant FIR filter provides filtering based on at least one of the group consisting of spreading and scrambling;
• b) means for storing each filter coefficient in a memory array in addressable groups corresponding to a filtering period;
• and
• c) means for filtering symbols to implement the combined time invariant FIR filter and time variant FIR filter using a polyphase decomposition of the filter coefficients to create a regenerated signal wherein filter calculations occur at a lower sampling rate and the regenerated signal is provided at a higher sampling rate.