초록 ▼

A method for the broadcasting of digital data, intended to be received notably by mobile receivers moving about in an urban environment, that is, under conditions of multiple propagation and in the presence of parasites and jamming, enabling a coherent demodulation under such conditions of reception

A method for the broadcasting of digital data, intended to be received notably by mobile receivers moving about in an urban environment, that is, under conditions of multiple propagation and in the presence of parasites and jamming, enabling a coherent demodulation under such conditions of reception. This method is one for the broadcasting of digital data, notably for radio broadcasting at a high bit rate towards mobile receivers, of the type providing for the distribution of the data in the form of digital elements in the frequency-time space f-t and the transmission of symbols each constituted by a multiplex of N orthogonal carrier frequencies modulated by a set of digital elements and broadcast simultaneously, certain of the digital elements being reference elements with a value and position in the frequency-time space f-t that are known to the receivers.

대표청구항 ▼

A receiver of a digital signal transmitted in a transmission channel on a plurality of orthogonal frequency carriers, said digital signal being formed of data elements grouped in symbols comprising first symbols and second symbols, at least two of said first symbols being inserted between any two of

A receiver of a digital signal transmitted in a transmission channel on a plurality of orthogonal frequency carriers, said digital signal being formed of data elements grouped in symbols comprising first symbols and second symbols, at least two of said first symbols being inserted between any two of said second symbols, said first symbols consisting entirely of N of said data elements and second symbols comprising N-P of said data elements and P reference elements, said reference elements being regularly distributed among said data elements in such a way that at least two consecutive data elements are inserted between each two reference elements, each of said symbols being transmitted on N orthogonal frequency carriers for simultaneous broadcast; the receiver comprising: means for recovering said reference elements and for estimating a response of the transmission channel consisting in a demodulation sample for each of said frequency carriers of said plurality of orthogonal frequency carriers, from the recovered reference elements, said means for recovering comprising: first means for interpolation filtering of the reference elements of a second symbol to recover demodulation reference samples for each data elements of said second symbol; second means for interpolation filtering of the recovered demodulation reference samples of said second symbols, on each of said frequency carriers for a set of successive data elements included between two successive second symbols to recover demodulation reference samples for each data elements of each of said first symbols; means for projecting each of the frequency carriers of said plurality of orthogonal frequency carriers on the corresponding demodulation sample of the estimated response of the transmission channel, carrying out a coherent demodulation of each of said frequency carriers.