Orange

France Telecom

Pierre Siohan

Hao Lin

Chrislin Lele

Youssef Dandach

Jean-Philippe Javaudin

Marc Lanoiselee

Rodolphe Legouable

Dinh Thuy Phan Huy

Maryline Helard

Bruno Jahan

Maurice Bellanger

Jean-Claude Carlac'h

Thierry Dubois

Naila Lahbabi

Didier Pinchon

Cyrille Siclet

Lionel Guivarch

Rodophe Legouable

The invention relates to precoding (or rather pre-equalization) for a faster-than-Nyquist OFDM or OFDM/OQAM type transmitter. Compression of faster-than-Nyquist OFDM pulses over time introduces an inter-symbol interference (ISI) and a sub-carrier interference (ICI). Assuming a Gaussian-type channel (AWGN), the ISI and ICI can be estimated at the transmitter and, in this way, some of the symbols (at most half) can be precoded (according to the value of the adjacent symbols), such as to cancel the ISI and ICI introduced during transmission and reception.

Precompensation of interference induced by an OFDM/OQAM modulation that is faster than Nyquist

A method is provided for transmitting complex data symbols, supplying a multiple carrier signal. The method includes shaping at least one block of M&#xd7;K complex data symbols, where M&#x3e;1 and K&#x3e;1, implementing the following acts: for at least one column of the block, conversion of the M complex data symbols of the column from the frequency domain to the time domain, supplying N converted symbols; cyclic repetition of the N converted symbols, supplying NK repeated symbols; cyclic repetition of the transformed N symbols, supplying NK repeated symbols; filtering the NK repeated symbols via a shaping filter, supplying NK filtered symbols; and summation of the obtained filtered symbols for the various columns of the block, supplying NK time samples.

Methods, devices pertaining to transmission of multi-carrier signal

A method is provided for modulating data symbols, outputting a multi-carrier signal, implementing: a mathematical transform, which transforms data symbols from the frequency domain to a time domain, outputting transformed symbols; and a polyphase filtering, which filters the transformed symbols, outputting the multi-carrier signal. The polyphase filtering uses an expansion factor taking account of a compression factor &#x3c4;, the compression factor &#x3c4; being a number between 0 and 1 such that the multi-carrier signal can be transmitted at a Faster-Than-Nyquist rate.

Modulation method and device delivering a multicarrier signal, and corresponding demodulation method and device and computer program

A method is provided for receiving an OQAM multi-carrier signal, which implements a step of estimating, in the time domain, at least one time, phase, and/or frequency shift of the multi-carrier signal. The estimation step implements at least one estimator in order to estimate the time shift, referred to as a time estimator, and/or at least one estimator for estimating the phase shift, referred to as a phase estimator, and/or at least one estimator for estimating the frequency shift, referred to as a frequency estimator. The multi-carrier signal includes at least one preamble, and at least one of the estimators takes into account coefficients of a prototype filter used in transmission in order to shape at least one preamble inserted into the multi-carrier signal.

Estimation of a time, phase and frequency shift of an OQAM multicarrier signal

The invention relates to a method of transmitting a signal comprising successive multi-carrier symbols with M subcarriers arranged in a frame, defined by a preamble comprising a first multi-carrier symbol: and a second multi-carrier symbol:  The pilot symbols pare such that: with &#x3b1;a real random variable.

Method for transmitting a signal with a preamble and corresponding devices, signal with corresponding preamble for synchronization of a receiver

A method is provided for determining at least one filter of a filter bank in a transmission or coding system, on the basis of a prototype filter. The method includes determining coefficients p[k] of the prototype filter, of length L equal to N, from &#x394; angle parameters &#x3b8;, for 0&#x2266;i&#x2266;&#x394;&#x2212;1, expressed on the basis of a polynomial function &#x192;(x), also referred to as a compact representation, such that: 

Method for determining at least one filter of a filter bank of a transmission or coding system, corresponding device and computer program

A method for multi-carrier transmission of a signal including OFDM blocks formed from N carriers modulated by a constellation symbol. The method includes, for at least one OFDM block: a phase of prebuilding M prebuilt complex time samples representative of the N carriers of the OFDM block, and a phase of correcting the constellation symbols modulating the N carriers, including the following acts, repeated for each carrier: detection of P samples having a power higher than a predefined threshold, delivering the P samples and M&#x2212;P zero samples, forming M complex time samples to be corrected, correcting the constellation symbol on the basis of the M complex time samples to be corrected, delivering an item of complex correction data, building M complex time samples associated with the item of complex correction data, and updating the M prebuilt complex time samples.

Method for reducing PAPR in a transmission of a multi-carrier signal, and corresponding transmission device and computer program

Disclosed is a transmission method of transmitting at least one multicarrier signal made up of OFDM-OQAM symbols to a receive antenna of a receiver device, the transmission method being for use by a transmitter device having at least one transmit antenna. In one embodiment, the method comprises, for each transmit antenna of the transmitter device, filtering OFDM-OQAM symbols associated with the transmit antenna using a time-reversal prefilter defined from an estimate of the transmission channel between the transmit antenna and the receive antenna and transmitting the filtered OFDM-OQAM symbols via the transmit antenna over the transmission channel.

Method for transmitting at least one multi-carrier signal consisting of OFDM-OQAM symbols

A method is provided for modulating a real data stream grouped into blocks of nb&#xb7;M real data, where M is the number of carriers and nb is an integer greater than or equal to 2. The method includes, for a block of real data: a first modulation by a first modulator of the first M/2 data, delivering a first set of modulated carriers; a second modulation by a second modulator of the following (nb&#x2212;1)&#xb7;M data, delivering a second set of (nb&#x2212;1)&#xb7;M modulated carriers; a third modulation by a third modulator of the last M/2 data, delivering a third set of modulated carriers; and a superposition of the first, second and third sets, forming a block of OFDM/OQAM symbols of length nb&#xb7;M/2, the first set being superposed with the start of the second set and the third set being superposed with the end of the second set.

Method, devices and computer program product for modulation and demodulation delivering OFDM/OQAM symbols

A modulator and modulation method are provided, which output an OQAM multi-carrier signal. The method implements a step of transforming, from the frequency domain to the time domain, a set of M symbols of real data so as to output M transformed symbols. The complete transformation includes the following sub-steps: applying a partial Fourier transform to the set of M symbols of real data, outputting a first subset of C transformed symbols, where C is strictly less than M; and obtaining, from the first subset, a second subset of (M-C) transformed symbols that is complementary to the first subset.

Method for modulating an OQAM type multi-carrier signal, and corresponding computer program and modulator

A weighting filter is provided for use in a device for transmitting and/or receiving an analog signal. The device is capable of transmitting and/or receiving the analog signal in a predetermined frequency band consisting of two adjacent sub-bands, referred to as first and second sub-bands. The weighting filter includes: a first branch, which attenuates the analog signal; a second branch that filters the analog signal and has a bandwidth corresponding to the first sub-band or to the second sub-band; and a module that combines signals from the first and second branches.

Weighting filter, and corresponding methods and devices for transmitting and receiving an analog signal and computer program

A method is provided for transmitting a multiple-carrier signal. The method includes modulating data symbols representative of a data signal to be transmitted, which includes a filtering by at least one prototype function using at least two different filtering coefficients, thus providing a modulated signal including a time sequence of multiple-carrier symbols. A hold interval is inserted in front of at least one multiple-carrier symbol of the modulated signal, thus providing the multiple-carrier signal.

Methods for transmitting and receiving a multicarrier signal comprising a guard interval, corresponding computer program products, transmitting and receiving devices, and signal

A method is provided for transmitting a multicarrier signal formed by a temporal succession of multicarrier symbols, which includes: at least one preamble formed by at least three successive multicarrier symbols, known as preamble symbols, including complex-value data elements each associated with a carrier of the signal; and multicarrier symbols, known as data symbols, including real-value data elements each associated with a carrier of the signal. The method includes a carrier-shaping step including filtering the carriers of the preamble symbols using a first prototype filter, and filtering the carriers of the data symbols using a second prototype filter different from the first prototype filter.

Methods for transmitting and receiving a multicarrier signal implementing prototype filters, corresponding devices for transmitting and receiving, signal and computer program

A method and apparatus are provided for transmitting a multicarrier spread-spectrum signal formed by a temporal succession of multicarrier symbols, using OQAM modulation and a plurality of inter-orthogonal spreading codes. The method includes spreading at least one complex-value data symbol, representative of a source data signal to be transmitted, over a set of sub-carriers of at least one multicarrier symbol, each of the sub-carriers modulating a complex value.

Methods for transmitting and receiving a multicarrier spread-spectrum signal, corresponding signal, computer program products and transmission and reception devices

A method is provided for receiving a received signal corresponding to a multicarrier signal transmitted by at least one transmitter via a transmission channel, the multicarrier signal being formed by a temporal succession of symbols including of a set of data elements with real values, including informative data elements, and reference data elements called pilots for at least some of the symbols. The reception method includes step of first estimation of the transmission channel. Due to at least one of the pilots being an isolated pilot in transmission, the reception method further includes a step of extracting the isolated pilot, and a step of locally refining the first estimation.

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Rennes, France

Pierre Siohan