Patent ID: 8014436

Claim:
A method for communicating data symbols resulting in a transmitted radio signal with a reduced ratio of peak amplitude to root-mean-square amplitude, said method comprising the steps of: simultaneously using multiple, additively-combined, spread-spectrum codes each carrying an In-phase or real signal value and a Quadrature phase or imaginary signal value to provide at least three independent modulation dimensions, each dimension carrying a coordinate value; defining a set of constellation points to be associated with the data symbols, the constellation points distributed within a space comprised of the at least three dimensions such that a Euclidean distance between any two of the constellation points is not less than a desired minimum and such that a desired peak amplitude value is not exceeded by any point, the peak value being determined by any of the following measures: a sum of absolute values of the coordinates of any constellation point corresponding to the dimensions provided by the real signal values carried by the multiple, additively-combined, spread-spectrum codes; a sum of the absolute values of the coordinates of any constellation point corresponding to the dimensions provided by the imaginary signal values carried by the multiple, additively-combined, spread-spectrum codes; and a sum of the squares of (a) the sum of the absolute values of the coordinates of any constellation point corresponding to the dimensions provided by the real signal values carried by the multiple, additively-combined, spread-spectrum codes; and (b) the sum of the absolute values of the constellation coordinates of any point corresponding to the dimensions provided by the imaginary signal values carried by the multiple, additively-combined, spread-spectrum codes; wherein a majority of the constellation points are on an outer surface of a diamond-shaped constellation defined in a three-dimensional space with coordinate axes X, Y and Z, the outer surface of the diamond-shaped constellation being defined by the boundary equation |X|+|Y|+|Z|=1; further comprising the steps of receiving and decoding said radio signal including the steps of: determining a facet of the diamond-shaped constellation on or within which a transmitted data symbol lies; determining a subset of points on the facet within which the transmitted data symbol lies; determining a point within the subset of points which is closest to the received coordinate values of the transmitted data symbol; and determining the transmitted data symbol from the combination of the facet, the subset of points, and the closest point, wherein said step of determining the transmitted data symbol further includes using a look-up table which is addressed by a facet number, a subset of points number and a closest point number.