The aim of this work is to improve the energy gain of signals by combined application of non-uniform hierarchical modulation and forward error correction codes. For two types of modulation (QPSK and QAM16) values of K that achieves the best BER performance at the predetermined signal-to-noise-ratio are found. Results of MatLab simulation shows that uncoded QPSK modulated signals with gain K = 4 BER curve are matched with the theoretical curve for QAM16. QPSK modulated and turbo-coded signals have the best BER performance when K = 2.5. An energy gain compared with the signals without application of hierarchical modulation (turbo-code and modulation QAM16) equal 1.5 dB. For turbo-coded and QAM16 modulated signals the best BER performance is achieved for K = 9. An energy gain compared with the signals without application of hierarchical modulation (turbo-code and modulation QAM256) equal 1 dB.