Bidirectional turbo ISI canceller-based DSSS receiver for high-speed wireless LAN

A system for reducing signal distortion in a receiver, comprising:

• channel matched filter which generates a sequence of chips from a received signal;
• a decision feedback equalizer (DFE) which cancels postcursor- inter-symbol interferance ISI from the chip sequence to produce a chip metric;
• and
• a code complementary keying (CCK) correlation-decision block which generates a current CCK codeword based on said chip metric, wherein the DFE cancels precursor-ISI from a previous CCK codeword based on a chip-time reversed estimate of the current CCK codeword.

A bidirectional turbo inter-symbol interface (ISI) canceler (BTIC), comprising:

• a single-symbol detector which generates a sequence of chips from a received signal;
• a postcursor-ISI canceler to generate postcursor-ISI cancellation terms from a previously detected chip sequence used to form a previous code complementary keying (CCK) codeword and to cancel postcursor-ISI from the chip sequence to produce a chip metric;
• and
• a precursor-ISI canceler to generate precursor-ISI cancellation terms based on a chip-time reversed estimate of a current CCK codeword generated from said chip metric to cancel precursor-ISI from the previous CCK codeword.

A method for reducing distortion in a receiver, comprising:

• computing a set of decision feedback equalizer (DFE) coefficients;
• canceling postcursor-inter-symbol interference (ISI) caused by a preceding symbol using the set of DFE coefficients;
• and
• canceling precursor-ISI caused by a trailing symbol using the same set of DEE coefficients, wherein said canceling postcursor-ISI and the canceling precursor-ISI are respectively performed in first and second feedback canceler units based on the set of DEE coefficients, wherein canceling the precursor-ISI because of the trailing symbol comprises:
• computing conjugates of chip values of a future symbol;
• setting the DFE coefficients based on the DFE coefficients;
• and
• subtracting the precursor-ISI terms from chio metrics to reduce the precursor-ISI.