Receiver with a decision feedback equalizer and a linear equalizer

A method for equalizing a received signal in a wireless communication system, comprising:

• adapting a decision feedback equalizer (DFE) based on the received signal for an initial time period;
• determining a quality metric based on a signal-to-interference-and-noise ratio (SINR) for an output of the DFE after the initial time period;
• selecting periodically either the DFE or a linear equalizer (LE) for use to equalize the received signal based on the quality metric;
• and
• if the LE is selected for use,
• deriving initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE, and
• adapting the coefficients of the LE for an additional time period prior to using the LE to equalize the received signal.

An adaptive equalizer suitable for use in a wireless communication system, comprising:

• a filter unit configurable to implement either a decision feedback (DFE) or a linear equalizer (LE), wherein the DFE or the LE is selected periodically for use to equalize a received signal depending on a quality metric based on a signal-to-interference-and-noise ratio (SINR) and determined for an output of the DFE;
• an adaptation unit operative to derive coefficients for the DFE or the LE depending on whether the DFE or LE is selected for use;
• wherein the filter unit is initially configured to implement the DFE;
• wherein the DFE is adapted based on the received signal for an initial time period and the quality metric is determined after the initial time period;
• and
• wherein if the LE is selected for use, the adaptation unit is further operative to derive initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE.

An adaptive equalizer suitable for use in a wireless communication system, comprising:

• a filter unit configurable to implement either a decision feedback equalizer (DFE) or a linear equalizer (LE), wherein the DFE or the LE is selected for use to equalize a received signal depending on a quality metric based on a signal-to-interference-and-noise ratio (SINR) and determined for an output of the DFE;
• and
• an adaptation unit operative to determine the quality metric for the DFE output, derive coefficients for the DFE or the LE depending on whether the DFE or LE is selected periodically for use, and if the LE is selected for use,
• derive initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE, and
• adapt the coefficients of the LE for an additional time period prior to using the LE to equalize the received signal.

A memory communicatively coupled to a digital signal processing device (DSPD) capable of interpreting digital information to:

• adapt a decision feedback equalizer (DFE) based on a received signal for an initial time period;
• determine a quality metric based on a signal-to-interference-and-noise ratio (SINR) for an output of the DFE;
• select periodically the DFE for use to equalize the received signal if the quality metric is better than a threshold value;
• select periodically a linear equalizer (LE) for use to equalize the received signal if the quality metric is worse than the threshold value;
• wherein the quality metric is determined after the initial time period;
• and
• wherein if the LE is selected for use, an adaptation unit is further operative to derive initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE.

A computer program product for equalizing a received signal in a wireless communication system, comprising:

• code for adapting a decision feedback equalizer (DFE) based on a received signal for an initial time period;
• code for determining a quality metric based on a signal-to-interference-and-noise ratio (SINR) for an output of the DFE;
• code for selecting periodically the DFE for use to equalize the received signal if the quality metric is better than a threshold value;
• code for selecting periodically a linear equalizer (LE) for use to equalize the received signal if the quality metric is worse than the threshold value wherein the quality metric is determined after the initial time period;
• and
• code wherein if the LE is selected for use, an adaptation unit is further operative to derive initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE
• a computer-usable medium for storing the codes.

An integrated circuit, comprising:

• a filter unit configurable to implement either a decision feedback equalizer (DFE) or a linear equalizer (LE), wherein the DFE or the LE is selected periodically for use to equalize a received signal depending on a quality metric based on a signal-to-interference-and-noise ratio (SINR) and determined for an output of the DFE;
• an adaptation unit operative to derive coefficients for the DFE or the LE depending on whether the DFE or LE is selected for use;
• wherein the filter unit is initially configured to implement the DFE;
• wherein the DFE is adapted based on the received signal for an initial time period and the quality metric is determined after the initial time period;
• and
• wherein if the LE is selected for use, the adaptation unit is further operative to derive values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE.

A receiver system in a wireless communication system, comprising:

• a receiver unit operative to process a received signal to provide data samples;
• and
• a data processor operative to process the data sample to provide equalized symbols, the data processor including
• a filter unit configurable to implement either a decision feedback equalizer (DFE) or a linear equalizer (LE), wherein the DFE or the LE is selected periodically for use to equalize a received signal depending on a quality metric based on a signal-to-interference-and-noise ratio (SINR) and determined for an output of the DFE;
• an adaptation unit operative to derive coefficients for th DFE or the LE depending on whether the DFE or LE is selected for use;
• wherein the filter unit is initially configured to implement the DFE;
• wherein the DFE is adapted based on the received signal for an initial time period and the quality metric is determined after the initial time period;
• and
• wherein if the LE is selected for use, the adaptation unit is further operative to derive initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE.

An apparatus in a wireless communication system, comprising:

• means for implementing a decision feedback equalizer (DFE) or a linear equalizer (LE) based on a quality metric wherein said quality metric is based on a signal-to-interference-and-noise ratio (SINR);
• means for adapting the DFE based on a received signal for an initial time period;
• means for determining said quality metric for an output of the DFE;
• means for selecting periodically either the DFE or the LE for use to equalize the received signal based on the quality metric;
• means for deriving initial values for coefficients of the LE based on coefficients of a feed-forward filter and a feedback filter for the DFE, if the LE is selected for use;
• and
• means for adapting the coefficients of the LE for an additional time period prior to using the LE to equalize the received signal, if the LE is selected for use.