The exponent of the error probability in various modulation and encoding systems

The probabilistic characteristics are investigated of two modulation and encoding systems in channels subjected to an additive white Gaussian noise. The systems enbody the principle of cascaded codes, with two-dimensional signals at the internal step and convolutionary or block codes at the outer step. Algorithms for design (encoding and modulation) and processing (demodulation and decoding) of such systems are discussed. The exponent is estimated of the error probability which characterizes the reliability of a communication systems.