Telediffusion De France

Centre National D'etudes Des Telecommunications

France Telecom

France Telecom, Telediffusion De France S.a.

Daniel Pommier

Damien Castelain

Jean-Claude Rahuel

Bernard Le Floch

Michel Alard

Jean-Christophe Rault

Roselyne Halbert-Lasselle

Joel Richard

A method for the transmission of digital data elements including radio paging information elements, wherein the data elements are transmitted according to a technique of transmission implementing a plurality of orthogonal carrier frequencies (the COFDM technique), the signal being organized in frames comprising, firstly, at least one first channel called a fast information channel, comprising at least one symbol of data elements, the carrier frequencies of the symbols being modulated by data elements that are not temporally interleaved, and at least one second channel, called a main channel, comprising at least one symbol of data elements, the carrier frequencies of the symbols being modulated by data elements that are temporally interleaved beforehand, a frame number belonging to a set of predefined frame numbers being regularly inserted into the fast information channel, each of the radio paging receivers being assigned at least one of the frame numbers.

Method for the transmission of digital data in radio paging systems and

A device for the reception of digital data broadcast at a high bit rate for reception by mobile receivers is disclosed. The device operates under adverse conditions of multiple propagation corresponding to the Rayleigh process and imperfect frequency tuning to minimize the inter-symbol interference in the frequency domain. The device receives a digital signal having digital elements distributed in the frequency-time space f-t and transmitted in the form of symbols each constituted by a multiplex of N orthogonal carrier frequencies modulated by a set of digital elements and broadcast simultaneously. The device includes a module for transposition by a local oscillator, baseband filtering and analog-digital conversion, a temporal windowing module for the selection of the useful samples and a mathematical transformation module, the temporal windowing module applying a Nyquist window type of temporal window with non-zero roll-off.

Device for the reception of digital data time frequency interlacing,

A method for the broadcasting of digital data, in channels to which multiple paths are assigned, the characteristics of which vary in time, with time-frequency interlacing and assistance in the acquisition of the automatic frequency control. This method is one 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 frames of symbols each constituted by a multiplex of N orthogonal carrier frequencies modulated by a set of the digital elements and broadcast simultaneously, the method providing for the transmission of a pattern of frequency synchronization, recurrent in time. It can be applied notably for radio broadcasting at a high bit rate towards mobile receivers, and for example, to COFDM radio broadcasting.

Method for the broadcasting of digital data, notably for radio

A digital broadcasting process, suitable for digital audiobroadcast, comprises encoding the data in the form of binary words using a redundant code to obtain a sequence of modulation symbols and transmitting the symbols in a plurality of subchannels at different frequencies. The symbols are time interlaced with such a distribution that two adjacent symbols cannot be transmitted in time succession and at the same one of the frequencies. Preferably, a Viterbi decoder is used. Particular construction of an emitter and a receiver are also described.

Method and installation for digital communication, particularly between

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Breal Sous Montfort, France

Daniel Pommier