Abstract: The invention concerns a pre-distortion method for a telecommunication system comprising a base station and at least one user. Each symbol of said user is spread with a coding sequence over a plurality of carriers to produce a plurality of corresponding frequency components of a signal (Si(t)) to be transmitted over an uplink transmission channel to said base station. Each of said frequency components is weighted by a weighting coefficient (?i(l)), said weighting coefficients being determined from the channel response coefficients (hi(l)) of the corresponding downlink transmission channel at the respective frequencies of said carriers and from a value of the noise variance (?2) affecting said carriers.

Abstract: The present invention concerns a method and a device for obtaining, by a first telecommunication device and from a second telecommunication device, information representative of the channel quality indication on at least one frequency subband, the first and the second telecommunication devices being linked through a wireless telecommunication network using a plurality of frequency subbands. The frequency subbands are grouped into groups of at least one frequency subband, and the first telecommunication device transfers a message to the second telecommunication device, the message comprising information identifying a first group of at least one frequency subband, receives, from the second telecommunication device, for each frequency subband comprised in the first group, an information representative of the channel quality indication determined by the second telecommunication device for the frequency subband comprised in the first group.

Abstract: Exemplary embodiments of the invention provide an equalization method for a downlink channel in a telecommunication system transmitting MC-CDMA symbols on a plurality of carrier frequencies, in which a plurality of links are established between a transmitter and a plurality of receivers in order to transmit a plurality of coded signals, each link using a distinct access code amongst N possible codes, the conjugate product of two possible codes being proportional to a possible code or to its conjugate, the method including, for at least one receiver, a step of calculating a matrix (B, B) characteristic of the plurality of links, the calculation step first of all calculating the elements of a row or a column in the characteristic matrix and deducing the other rows or the other columns by means of a permutation of the elements.

Abstract: An equalization method and apparatus for a downlink channel in a telecommunication system transmitting MC-CDMA symbols on a plurality of carrier frequencies, in which a plurality of links are established between a transmitter and a plurality of receivers in order to transmit a plurality of coded signals, each link using a distinct access code amongst N possible codes, there being P links for P users where P is less than N. The equalization including the formation and use of a matrix of reduced size based upon the number of links being P by eliminating matrix elements relating to the unused codes and effecting an estimation of the said transmitted symbols according to a mean square error minimization criterion.

Abstract: The present invention on concerns a method of assigning one or more spreading sequences to a user of a Multi-Carrier Code Division Multiple Access transmission network, each element of the said sequence being, at a transmitter of the said network, multiplied by a data item to be transmitted and then transmitted on a corresponding sub-carrier. According to the present invention, it consists of assigning, to the said user, the said spreading sequence or the said spreading sequences taking into account a predetermined set of spreading sequences.

Abstract: The present invention concerns a method for obtaining an error correcting code of a given first size (N), including a systematic information part of a given second size (K) and a redundancy part. A block turbo-code is first obtained from said systematic information part and from predetermined information elements provided at known locations, said block turbo-code consisting in a product of elementary systematic block codes, at least said predetermined information elements being removed from the obtained block turbo-code to produce a shortened block turbo-code. An additional error correcting code is derived from at least a portion of said shortened block turbo-code and said shortened block turbo-code is stuffed with stuffing elements so as to attain said given first size, said stuffing elements being information elements of said additional error correcting code.

Abstract: An apparatus and method for a Multi-Carrier Code Division Multiple Access (“MC-CDMA”) transmission network is disclosed. In the MC-CDMA transmission network a plurality of spreading sequences are assigned to individual users from a plurality of predetermined spreading sequences. The spreading sequences are assigned to users in order to minimize the interference created by the assignment of spreading sequences.

Abstract: The present invention concerns a device and a method of dynamically assigning subgroups of spreading sequences of a set of spreading sequences to mobile terminals of a Multi-Carrier transmission network, characterised in that each subgroup comprises different spreading sequences than the spreading sequences comprised in other subgroups, each subgroup of spreading sequences comprising a first spreading sequence and at least one other spreading sequence, each element of the first spreading sequence being, by the mobile terminal of which the first spreading sequence has been assigned, multiplied by pilot symbols to be transmitted and then transmitted on a corresponding sub-carrier and each element of the at least one other spreading sequence being, by the mobile terminal of which the spreading sequence has been assigned, multiplied by data symbols to be transmitted and then transmitted on a corresponding sub-carrier. The method comprises also the equalization device and the method associated.

Abstract: The present invention relates to a method for transmitting data between a transmitter TR and a receiver REC via communication channels CHNL. The method according to the invention further includes a symbol spreading step in the course of which a tunable integer number K of successive symbols Z1 . . . ZK are to be spread over several time chips before being transmitted, said tunable number K being adjusted with respect to physical properties of the communication channels CHNL. The data transmitted at any given moment will thus not be representative of a single symbol Zi, as is the case in known MIMO systems, but will represent a mixture between K successive symbols, which introduces data diversity with respect to time as perceived at the receiver end, and enables a tuning of the communication throughput between the transmitter TR and the receiver REC.

Abstract: The present invention concerns a method of dynamically assigning spreading sequences of a group of spreading sequences to users of a Multi-Carrier transmission network and/or to at least a common signal for a plurality of users of the Multi-Carrier transmission network, each element of the said spreading sequences being, at a transmitter of the said network, multiplied by data items to be transmitted and then transmitted on a corresponding sub-carrier, characterised in that the spreading sequences are put in a natural order in the group of spreading sequences and the method comprises the step of dynamically assigning the spreading sequences of the group of spreading sequences according to their order in the group of spreading sequences to users of the Multi-Carrier transmission network and/or to at least a common signal to a plurality of users of the Multi-Carrier transmission network.

Abstract: A method of transmitting data on multiple carriers is disclosed, the method consisting, on a transmitter side, of binary to signal coding of the data to be transmitted so as to form modulation signals, of modulating a plurality of sub-carriers with the modulation signals as to form symbols, referred to as OFDM symbols, and then of transmitting, over a channel between the transmitter and a receiver, the OFDM symbols at a rate which is related to a sampling frequency referred to as the transmitter sampling frequency, and, on the receiver side, of determining, from a clock signal at a frequency related to a sampling frequency referred to as the receiver sampling frequency, an analysis window for the signal received from the transmitter so as to form a block of samples, and of estimating the transmitted modulation signals by demodulating the sub-carriers for the block of samples under consideration.

Abstract: The present invention relates to a method for transmitting data Di in a telecommunication system SYST including a first transceiver TXi and a second transceiver RX linked together by means of a communication channel Chi, one of which transceivers being mobile, which method includes: a spreading step for spreading said data Di over a plurality of components Ctj (for j=1 to M), and an equalization step during which each component Ctj, (for j=1 to M) is multiplied by an equalization value Wi(j)* representative of communication conditions within the communication channel Chi. According to the invention, the equalization values Wi(j)* are also representative of a Doppler effect generated by movement of the mobile transceiver. The invention enables to significantly compensate for alterations caused to the communication channel Chi by movement of the mobile transceiver.

Abstract: The invention concerns a pre-distortion method for a telecommunication system comprising a base station and at least one user. Each symbol of said user is spread with a coding sequence over a plurality of carriers to produce a plurality of corresponding frequency components of a signal (Si(t)) to be transmitted over an uplink transmission channel to said base station. Each of said frequency components is weighted by a weighting coefficient (&ohgr;i(l)), said weighting coefficients being determined from the channel response coefficients (hi(l)) of the corresponding downlink transmission channel at the respective frequencies of said carriers and from a value of the noise variance (&sgr;2) affecting said carriers.

Abstract: The invention concerns a pre-distortion method for a telecommunication system comprising a base station and at least one user. Each symbol of said user is spread with a coding sequence over a plurality of carriers to produce a plurality of corresponding frequency components of a signal (Si(t)) to be transmitted over an uplink transmission channel to said base station. Each frequency component is weighted by a weighting coefficient (&ohgr;i(l)), said weighting coefficient being determined from the downlink channel response coefficient (hi(l)) at the corresponding frequency and from a value of the noise variance (&sgr;2) affecting said carriers.

Abstract: The present invention concerns a method for obtaining an error correcting code of a given first size (N), including a systematic information part of a given second size (K) and a redundancy part.

Abstract: A method and apparatus for estimating the speed of relative movement of a transmitter and a receiver which are in communication with each other in a telecommunications system. The transmitter and receiver are in communication via a channel of the telecommunications system by a carrier wave. An analysis is made of the variations of amplitude or power of the signal transmitted by the transmitter and the channel between the transmitter and the receiver. The dopler shift undergone by the carrier wave is deduced from the variations, and the speed of movement is thereby deduced.

Abstract: Equalisation method for a downlink channel in an MC-CDMA telecommunication system in which a plurality of links are established between a transmitter and a plurality of receivers, each link using a distinct access code amongst N possible codes, the method comprising a first step (450, 460) of estimating the relative levels ({circumflex over (&ngr;)}i) of the signals transmitted by the transmitter by means of each of the said N codes, the said first step including an equalisation (431) of the MC-CDMA symbols carrier by carrier, and a second step (580, 680) using the said levels for estimating the symbols transmitted by the user over at least one link, the said second step being adapted to minimise the mean square error between the said transmitted symbols and the estimated symbols.

Abstract: Equalization method for a downlink channel in a telecommunication system transmitting MC-CDMA symbols on a plurality of carrier frequencies, in which a plurality of links are established between a transmitter and a plurality of receivers in order to transmit a plurality of coded signals, each link using a distinct access code amongst N possible codes, the conjugate product of two possible codes being proportional to a possible code or to its conjugate, the said method comprising, for at least one receiver, a step of calculating a matrix (B, E) characteristic of the said plurality of links, the said calculation step first of all calculating the elements of a row or a column in the characteristic matrix and deducing the other rows or the other columns by means of a permutation of the said elements.

Abstract: Equalisation method for a downlink channel in a telecommunication system transmitting MC-CDMA symbols on a plurality of carrier frequencies, in which a plurality of links are established between a transmitter and a plurality of receivers in order to transmit a plurality of coded signals, each link using a distinct access code amongst N possible codes, the method providing that, for at least one receiver, a vector (Y) representing the components of the signal received by the receiver on the different carrier frequencies is subjected to a filtering step adapted for supplying an observable vector (Z, Z′) and the said observable vector is used for effecting an estimation of the said transmitted symbols according to a mean square error minimisation criterion.

Abstract: A method for the time synchronization of a multi-carrier signal receiver consisting of a sequence of symbols each formed by a plurality of carrier frequencies. Each carrier frequency is modulated by a modulation coefficient. The position of some of said carrier frequencies in the time-frequency space is known to the receiver, and said frequencies are reference carrier frequencies. Each reference carrier frequency bears a reference coefficient with a value that is known to the receiver. The method includes a fine synchronization step, wherein the signal transmission channel impulse response is estimated on the basis of reference coefficients belonging to at least two received symbols. The beginning of the useful portion of each of the symbols is determined, and/or a receiver clock is controlled by analyzing the estimate of said impulse response.