Abstract: A method for estimating a range of a moving target includes emitting, from a target, a first ultrasound signal T, wherein the first ultrasound signal T is generated based on a first differential Zadoff-Chu sequence x; receiving, at a receiver, a second ultrasound signal R, which corresponds to the first ultrasound signal T, wherein the second ultrasound signal R includes a second differential Zadoff-Chu sequence y; applying a maximum likelihood estimator to the first ultrasound signal T and the second ultrasound signal R to calculate an initial time of flight estimate taucorr; and calculating an initial range estimate dcorr of the target by multiplying the initial time of flight estimate taucorr with a speed of sound c. A differential Zadoff-Chu sequence is different from a Zadoff-Chu sequence.

Abstract: A method for estimating a range of a moving target, the method including emitting, from a target, a first ultrasound signal T, wherein the first ultrasound signal T is generated based on a first differential Zadoff-Chu sequence x; receiving, at a receiver, a second ultrasound signal R, which corresponds to the first ultrasound signal T, wherein the second ultrasound signal R includes a second differential Zadoff-Chu sequence y; correlating the first ultrasound signal T with the second ultrasound signal R to calculate an initial time of flight estimate taucorr; and calculating an initial range estimate dcorr by multiplying the initial time of flight estimate taucorr with a speed of sound c. A differential Zadoff-Chu sequence is different from a Zadoff-Chu sequence.

Abstract: A method for estimating a range of a moving target includes emitting, from a target, a first ultrasound signal T, wherein the first ultrasound signal T is generated based on a first differential Zadoff-Chu sequence x; receiving, at a receiver, a second ultrasound signal R, which corresponds to the first ultrasound signal T, wherein the second ultrasound signal R includes a second differential Zadoff-Chu sequence y; applying a maximum likelihood estimator to the first ultrasound signal T and the second ultrasound signal R to calculate an initial time of flight estimate taucorr; and calculating an initial range estimate dcorr of the target by multiplying the initial time of flight estimate taucorr with a speed of sound c. A differential Zadoff-Chu sequence is different from a Zadoff-Chu sequence.

Abstract: An iterative process for TDMA radiomobile communications where several reference sequences are distributed in each allocated timeslot. On reception, a multipath channel mesh representation and an iterative process are used.

Abstract: Method for optimal estimation of a propagation channel based solely on pilot symbols. A base of natural vectors is formed using the correlation matrix of the channel observed solely at the positions of the pilot symbols. Channel representation is broken down in this base. The base vectors are extended to the data symbols, which allows optimal interpolation of channel estimation to the data symbols. Application to OFDM, TDMA and CDMA systems.

Abstract: An Orthogonal Frequency Division Multiplexing reception method and receiver for receiving a signal representing data symbols through a plurality of channels and for supplying an estimation of the data symbols. The receiver includes a plurality of branches of diversity processing blocks. Each block includes data and pilot symbols distributed within a bi-dimensional time-frequency block. The receiver includes a channel estimator which receives the output signals supplied from the various branches of diversity, and provides a flexible estimation of the data symbols. The channel estimator processes a finite number of iterations in accordance with an expectation-maximization algorithm taking into consideration the pilot symbols of a bi-dimensional time-frequency block, and the pilot and precedent flexible data symbols estimated for following iterations until the finite number of iterations is reached.

Abstract: A CDMA radiocommunication signals receiver for receiving signals obtained from spectrum symbols spread using pseudo-random sequences and having been propagated along a number of paths. The receiver includes a filter configured to restore L unspread signals for each symbol, corresponding to L different paths, a calculating circuit configured to calculate L estimates of the L different paths, and a demodulator configured to process each of the L unspread signals using the corresponding L estimates to obtain L path contributions. Also included is an adder configured to form a sum of the L path contributions and for outputting an estimate of a received symbol, and a decision circuit configured to make a decision about a value of the received symbol based on a value of the estimate of the received symbol output by the adder.

Abstract: Method for optimal estimation of a propagation channel based solely on pilot symbols.

Abstract: A process for improving the reception quality of a Code Division Multiple Access (CDMA) signal that judiciously distributes reference symbols between two CDMA signal components, namely an in phase component (I) and quadrature component (Q). The reference symbols are distributed in only one of the two components, namely the I or Q component. To further improve the reception quality, the pseudo-random spreading sequence used for one of the components is different from the pseudo-random spreading sequence used for the other component. The applications of this process include mobile land radio communications.

Abstract: A digital signal is organized in consecutive data trains each comprising a predetermined number of successive symbols, each of said data trains comprising at least two distinct reference blocks for the estimation of said channel, distributed among the useful symbols representing the source signal to be transmitted, each of said reference blocks being formed by at least one reference symbol known to the receiver and/or identifiable by said receiver. The reference symbols present in the reference blocks may be explicit reference symbols that are fixed and known a priori by said receiver and/or implicit reference symbols produced by the links generated between the useful symbols by an encoding operation. Also disclosed are channel estimation methods implementing an estimation-maximization algorithm and/or using a combination of predetermined basic functions, with a bandwidth greater than or equal to the Doppler power spectrum of said signal.