Spectral and power shaping mapper for high data rate signalling

Abstract

A spectral and power shaping mapper for high data rate signaling modem is provided. Based on data rates and other criteria, groups of incoming bits are grouped together, with a first subgroup of bits being used to generate two sign vectors, a second subgroup of bits being used in conjunction with an appended bit to generate two magnitude manipulation vectors, and a third subgroup of bits being used in a modulus converter to generate a plurality of quotients (r.sub.k). The quotients and magnitude manipulation vectors are used to select two or more sequences of constellation points from a multidimensional constellation. The sequences of selected points are combined with the sign vectors to generate four sequences of octets for a shaping selector. The shaping selector, preferably in the form of a convolutional encoder state machine uses criteria such as lowest cost paths and/or lowest average power in order to select which sequence of octets to output.