Using QAM-9 and ternary noise-immune codes to approach the Shannon bound

摘要

Analysis of experimental results of the binary noise-immune coding with one-dimensional modulation best achievements points out the impossibility of achievement the continuous Gaussian channel parameters of such scheme in practice. In the paper is exhibited that changeover to more effective two-dimensional non-binary PAM modulation with ternary noise-immune codes in each quadrature branch of a modem allows to work with high enough reliability and to reach frequency-energetical system parameters that are equal to analogous parameters of continuous channel with AWGN. Symbol error probability Qs=10-4 for Eb/N0=4.963 and total spectral efficiency 4.036 bit/s/Hz have achieved for best modulation and coding scheme from proposed set.