Method for broadcasting digital data, especially towards mobile stations, with a high bit rate, with time-frequency interweaving and analogous synchronisation.

摘要

The field of the invention is that of broadcasting of digital data which are intended to be received especially by mobiles moving in an urban environment, that is to say in the presence of interference and jamming, and in multipropagation conditions (RAYLEIGH process). The invention relates to a method of broadcasting digital data in which the data are distributed in the form of digital elements in frequency f/time t/space, and the transmission of frames of symbols each consisting of a multiplex of orthogonal carrier frequencies modulated by a set of digital elements, and broadcast simultaneously over J parallel channels, the modulation being phase modulation with four phase states, each carrier frequency of the said multiplex being modulated by a pair of digital elements. The said pairs of digital elements are made up from a source sequence of digital elements, by constituting packets of 2J consecutive elements in the said source sequence, and by associating the elements in pairs in each packet according to a criterion of maximising the dispersion of adjacent digital elements of the source sequence. Frequency and time-based interlacing modes are also presented.