Patent ID: 6721357
Filing Date: 2004-04-13
Classification: H04L

Abstract:
A client modem operatively connected to a server modem through a communications system, said client modem including means for generating data constellations from non-uniform spaced super constellations for exchange of symbols between said client modem and said server modem based upon signals having a bit rate and received from said server modem at said client modem, said means for generating constellations comprising:means for approximating symbol error probability function of a data constellation for an observed noise variance by a function of the ratio between the minimum distance between adjacent symbols in the data constellation and the observed noise variance, multiplied by a density ratio of the data constellation, means for estimating a first minimum distance between adjacent symbols in the data constellation based upon expected symbol error probability selected according to the retransmission overhead of different operation modes; means for calculating a first density ratio of data constellation based upon said first minimum distance; and means for directing iterative recalculations of additional density ratios of data constellation and minimum distances between adjacent symbols in the data constellation until a final minimum distance is found that satisfies predetermined system requirements.