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

摘要

The field of the invention is that of the broadcasting of digital data intended to be received in particular by mobile stations travelling in an urban environment that is to say in the presence of disturbances and interference, and under multi-propagation conditions (Rayleigh process). The aim is to provide an optimised embodiment of the frame structure of the broadcast signal, so as to benefit to the maximum from the self-synchronising properties of the COFDM method, and to maximise the resistance of the system to pulsed disturbances and to interference. According to the invention, the recovery of synchronisation of each frame received is carried out by analogue synchronisation means, without prior retrieval of the clock signal. Advantageously, the frame header (21) comprises a first vacant synchronisation symbol (24) and a second unmodulated wobbulated symbol (25) forming a two-stage analogue synchronisation system. The make-up of the sequence of useful symbols (23) in the frame results from temporal and sequential interleaving operations, combined to obtain an implicit de-interleaving at the receiver. The vacant symbol (24) can serve moreover for extracting the interference affecting the transmission channel.