Method and system for modulating and detecting high datarate symbol communications

  • US 7,254,188 B2
  • Filed: 12/16/2003
  • Issued: 08/07/2007
  • Est. Priority Date: 12/16/2003
  • Status: Active Grant
First Claim
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1. A receiver comprising:

  • a demodulator for receiving symbol signal frames and producing quadrature demodulated output signals;

    a mapping look-up unit coupled to said demodulator for receiving said quadrature demodulated output signals and determining a three-bit symbol decode associated with points on a predetermined constellation, wherein said constellation has the property of having a first and second point of differing amplitude and zero reference phase, a third point having an amplitude equal to an amplitude of said first point and a 180 degree reference phase, a fourth point having an amplitude equal to an amplitude of said second point and a 180 degree reference phase, fifth and sixth points having real magnitudes substantially equal to said amplitude of said first point and equal imaginary magnitudes of opposite sign, and seventh and eighth points having real magnitudes substantially equal to a negation of said amplitude of said first point and equal imaginary magnitudes of opposite sign, wherein said mapping look-up unit produces probability values for each bit in said three-bit symbol decode from log-likelihood grouping maps for determining membership within a grouping associating said points with values of each bit of said three-bit symbol decode, whereby magnitudes of said quadrature demodulated output signals determine whether or not each symbol signal frame has membership in a first subgroup corresponding to a logical zero or membership in a second subgroup corresponding to a logical one for each grouping; and

    a codec coupled to an output of said mapping lookup unit for receiving said probability values for each bit and determining values of each bit.

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