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ROBERTO PADOVANI, University of Massachusetts - Amherst


Channel coding combined with expanded signal sets has been shown to improve error performance over uncoded modulation without expanding the bandwidth of the transmitted signals. Remarkable coding gains are obtainable by combining rate R(,c) = m/(m+1) convolutional encoders with 2('m+1)-point signal constellations, for transmission of m bits of information per modulation interval.^ The redundancy introduced in the signal space can be effectively exploited by a maximum-likelihood decoder (Viterbi decoder) to improve error performance as compared with uncoded transmission of the same information.^ The same approach is applied to new modulation formats that combine amplitude, phase, and frequency modulation. Several new codes are presented and their performance analyzed on both the additive white Gaussian noise channel and a bandlimited channel.^ The spectral characteristics of the proposed codes are derived and compared with those of conventional two-dimensional modulation formats. Finally, phase recovery and differential encoding to resolve phase ambiguities are discussed. ^

Subject Area

Engineering, Electronics and Electrical

Recommended Citation

ROBERTO PADOVANI, "SIGNAL SPACE CHANNEL CODING: CODES FOR MULTILEVEL/PHASE/FREQUENCY SIGNALS" (January 1, 1985). Doctoral Dissertations Available from Proquest. Paper AAI8509586.