Patent ID: 7239668

Claim:
A digital modulation method for efficient transmission of information, comprising: generating a stream of modulation symbols; and mapping said modulation symbols to a multi-ring digital signal constellation in order to produce a modulated signal, said multi-ring digital signal constellation comprising a number of digital signal points equally spaced on at least two concentric rings having respective predetermined radii, the number of digital signal points on each ring increasing monotonically with the ring radius, and the digital signal points on each ring having a predetermined relative phase shift with respect to the signal points on the other rings, transmitting said modulated signal through a trasmission channel, wherein, for a multi-ring signal constellation with normalized power, at least a ratio of the radii of said concentric rings is chosen so as to maximize a minimum geometrical distance between pairs of points of said multi-ring digital signal constellation in which the number of digital signal points on each ring increases monotonically with ring radius, in order to optimize the transmission of said modulated signal.