FIELD: high-speed digital data transmission systems operating under multibeam propagation conditions. SUBSTANCE: upon internal convolution encoding in orthogonal frequency-division multiplexing system using external Reed-Solomon coder and internal convolution coder data bits are interleaved and then grouped into characters, each incorporating m bits. After grouping characters are displayed on complex surface using quadrature amplitude modulation. In this way bits, and not characters, are interleaved by means of internal interleaving unit. Receiver executes soft solution including values of each bit in each quadrature amplitude modulated complex character received. EFFECT: enhanced speed of digital data transmission. 21 cl, 4 dwg, 1 tbl
