Power efficient equalization

A communications system comprising:

• a transmitter for transmitting a message;
• a receiver for receiving the transmitted message, said receiver further including;
• a pre-filter;
• an equalizer;
• a channel estimator for estimating a quality parameter and a number of channel filter taps using the received message;
• and
• a controller for evaluating the estimated quality parameter and the estimated number of channel filter taps to determine a number of pre-filter taps used in said pre-filter and a number of equalizer taps used in said equalizer where the number of equalizer taps is less than or equal to the estimated number of channel filter taps.

A method for determining the number of taps to be used in a pre-filter and an equalizer, both of which are components of a receiver, said method comprising the steps of:

• storing a message;
• estimating a quality parameter and a number of channel filter taps using the stored message;
• and
• evaluating the estimated quality parameter and the estimated number of channel filter taps to determine a number of pre-filter taps to be used in said pre-filter and a number of equalizer taps to be used in said equalizer where the number of equalizer taps is less than or equal to the estimated number of channel filter taps.

A method for reducing the power consumption within a mobile phone by adjusting the number of taps used in a pre-filter and an equalizer, said method comprising the steps of:

• storing a message;
• estimating a quality parameter and a number of channel filter taps using the stored message;
• and
• evaluating the estimated quality parameter and the estimated number of channel filter taps to determine a number of pre-filter taps to be used in said pre-filter and a number of equalizer taps to be used in said equalizer;
• calculating pre-filter coefficients using the estimated quality parameter, the estimated number of channel filter taps and the determined number of pre-filter taps;
• filtering the stored message using the determined number of pre-filter taps and the calculated pre-filter coefficients;
• and
• equalizing the filtered message using the determined number of equalizer taps.

An apparatus for minimizing the computational load in a pre-filter, said apparatus comprising:

• a channel estimator for estimating a quality parameter and a number of channel filter taps using a stored signal;
• and
• a controller, coupled to said channel estimator, for evaluating the estimated quality parameter and the estimated number of channel filter taps to determine a number of pre-filter taps, if any, to be used in said pre-filter;
• a pre-filter calculation controller, coupled to said controller, for calculating pre-filter coefficients using the estimated quality parameter, the estimated number of channel filter taps and the determined number of pre-filter taps, and for forwarding the calculated pre-filter coefficients to said pre-filter.