Alcatel N.v.

Alcatel Mobile Communication France

Alcatel Cit

Christophe Mourot

Vinod Kumar

Armelle Wautier

Jean-Claude Dany

Evelyne Le Strat

Marc Delprat

Fabrice De Seze

Rene Olivier

In a mobile radio system including mobile terminals each terminal comprises, on the receiving side, a unit using the Viterbi algorithm for equalization or for decoding the received signals after demodulation. A decision device of this system calculates the mean and the standard deviation of the metrics of each branch of the Viterbi algorithm, determines a quality level of a transmission parameter corresponding to the results of this calculation and compares the estimated quality level and a required quality level of the parameter in order to produce a decision signal supplied to a decision unit which can modify one or more transmission characteristics.

Device for making decisions by estimating the viterbi algorithm in a

Air interface adapting method for a mobile radio system

A receive processor device, in particular for a digital mobile radio system, includes a processor system comprising a set of functional units connected in cascade, some of which are decision units adapted to make decisions as to the value of information symbols that they receive. The decision unit is bypassed in the processor system and the value of information symbols to be processed by the next unit is deleted if the transmission quality of information symbols received by a decision unit is poor. Probable values for the deleted information symbols are determined from deleted information symbols and from undeleted information symbols received by the next unit.

Receive processor device for use in a digital mobile radio systems

In a system for transmitting information via a time-varying transmission channel, learning information is transmitted in addition to wanted information to enable the transmission channel to be estimated at the receiving end. The system estimates if it is necessary to transmit learning information given the current variations of the transmission channel and transmits learning information only if this is deemed necessary.

System for transmitting learning information via a time-varying

Encoding/interleaving method and corresponding deinterleaving/decoding

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

In a method of transmitting information at high speed by allocation of multiple bursts within a transmission frame each including information symbols and system symbols a user is allocated a plurality of adjacent bursts and at least one of the system symbols between the information symbols of the first of the adjacent bursts and the information symbols of the last of the adjacent bursts is replaced with an information symbol to form a superburst. The associated receiving method includes a stage for recognizing reception of a superburst and a stage for processing the superburst to extract the information symbols from it. There are applications relating to transmission and reception equipments of mobile radio communication systems.

Method for transmitting information at high speed by multiple burst

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 threshold detector for digital signal transmission systems using a transmission channel, in particular for transmission to mobiles, calculates a set of coefficients f.sub.n belonging to the group comprising a set of coefficients c.sub.n of the correlation between a first series of digital samples x.sub.n received by the receiver and a second series of reference digital samples p.sub.n known to the receiver, in order to acquire synchronization of the system, and a set of coefficients h.sub.n of an estimate of the impulse response of the transmission channel, when the system is already synchronized. It also calculates a decision variable A such that: ##EQU1## where L and N are predetermined integers. The device has many applications in mobile radio systems, for example for acquisition of synchronization in DS-CDMA systems or for optimizing the transmission channel estimate.

Threshold detector for digital radio transmission systems, devices

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.

Method for determining the transmittance of a filter circuit adapted to

A channel estimation device receives at one end of the channel a training sequence corresponding to a learning sequence produced at the other end of the channel. The estimation device generates a replica of the learning sequence and establishes the correlation of the learning and training sequences in order to produce a set of correlation coefficients. The estimation device includes a corrector device for eliminating the coefficients having the lowest moduli. The criteria used for eliminating the lowest moduli coefficients is that the sum of the squares of the moduli of the eliminated coefficients is less than a fraction of the sum of the squares of the moduli of all the correlation coefficients.

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Asnieres, France

Christophe Mourot