Alcatel N.v.

Alcatel

Armelle Wautier

Jean-Claude Dany

Christophe Mourot

Vinod Kumar

Jacques Antoine

Patrick Georges Charriere

Jérôme Brouet

Lionel Husson

Nicolas Paul

J&eacute;r&ocirc;me Brouet

A method of decoding a received data word (r) having been transmitted over a radio communication channel, the corresponding sent data word (m) having been encoded as a code word (c), the method includes: multiplying of the received data word by a parity-check matrix, and if the result of the multiplication is zero: performing an algebraic decoding of the received data word without error correction, otherwise performing an error correction by estimating the transmission error, subtracting the estimated error from the received data word, and performing an algebraic decoding of the result of the subtraction, wherein for estimation of the transmission error is used to identify an approximate location of potential errors and the Viterbi algorithm is only applied for these locations, thus avoiding iterations in error-free areas.

Method of decoding a data word

In a method of communicating with a mobile station in a cell of a cellular telecommunication network having a microcell layer with a plurality of microcells each comprising at least one relay station and a macrocell layer with a macrocell covering a plurality of microcells, a call in the microcell layer is effected between the mobile station and a set of relay stations, the number of which is a cardinal number at least equal to two, allocated to the call. The relay stations allocated to the call can change during the call, and the call is handed over from the microcell layer to the macrocell layer when it is not possible to allocate to the call a number of relay stations corresponding to the cardinal number. A base transceiver station for implementing the invention is also disclosed.

Handover from a microcell layer to a macrocell layer in a two-layer cell of a telecommunication network

A method for adjusting the length of a data block in a time-division multiple access communication system includes estimating the impulse response of a communication channel from received symbols of a reference sequence, estimating a signal-to-noise ratio from the channel impulse response, and estimating a maximum Doppler shift. Using these estimations, upper and lower limit functions of a normalized estimated mean squared error are calculated, and the length of the data block is adjusted to an optimal length determined from the upper and lower limit functions.

Method of adjusting the length of a data block in a time-division

The present invention concerns a learning sequence for estimating a transmission channel and an estimator device adapted to use a sequence of this kind. The learning sequence for estimating a transmission channel of length L comprises a guard sequence of length L followed by a reference sequence of length N such that its total length N+L is greater than or equal to 2L+1 and such that the transmission matrix A associated with it defined by the product of the Hermitian transpose A.sup.H of the transmission matrix by the transmission matrix A is inversible.

Learning sequence for estimating a transmission channel and

In mobile radio communications systems using time-division multiple access (TDMA), intersymbol interference caused by time differences in multipath media is avoided by equalizing data blocks. When a data block (BD) is received, the impulse response of the channel on which the block was transmitted is estimated, a set of receive parameters (PP) is evaluated, an optimal length (Nopt) of the block (BD) is determined from the parameters (PP), and when the optimal length (Nopt) is less than the actual length (N) of the block (BD), channel variation tracking (PO) is undertaken.

Method of equalizing a receive data block in a time-division multiple

A method for determining the transmittance of a filter circuit adapted to transform the impulse response of a filter into a minimal phase response entails computing the theoretical frequency response of the filter circuit and the minimal phase frequency impulse response with a causality condition applied to the cepstrum of the minimal phase response, determining the theoretical transmittance as the inverse fast Fourier transform of the theoretical frequency response, estimating the transmittance of the filter circuit by truncation of the theoretical transmittance of which only a predetermined number of coefficients are retained and determining the minimal phase global response from a limited expansion of the cepstrum.

Growing community of inventors

Gif sur Yvette, France

Armelle Wautier