New spectrally and energy-efficient signal-code construction (SCC) based on Index Modulation aided OFDM and Space-Time Block Coding, and also its noise-immune version in phase instability conditions with Inter-Channel Interference compensation operator, built intoAlamouti's coder structure, and increasing signals frequency diversity operator (Walsh-Hadamard) are proposed. In a complicated interference environment, first of all, under the influence of electronic suppression means, such methods increase simultaneously the data rate and reliability of digital information transmission. The SCCs enhance the noise immunity of the new generation wireless systems, as well as modern wireless communication networks of special purpose, which require high-quality implementation of bulky multimedia applications with high energy efficiency, in conditions of limited energy resources with spectral efficiency up to 4 bits/s/Hz. Using two transmit and no more than a pair of receive antennas guarantees the minimum weight-dimensional characteristics of mobile stations while providing the necessary level of antenna space decorrelation. The highest informational efficiency of such methods is achieved by applying reference look-up tables for short subblocks and small signal constellations, which allows the practical implementation of an optimal Maximum Likelihood Detector based on modern digital signal processors.Електронне наукове фахове виданняжурнал «Проблеми телекомунікацій»• № 1 (24) • 2019 • http://pt.nure.ua