Abstract: The present invention relates to a differential space-time coding of blocks of 2, 4 or 8 information symbols belonging to a 2-PPM modulation alphabet, for a pulse UWB MIMO system with 2, 4 or 8 transmitter antennas. The proposed differential space-time code does not introduce an inversion of the polarity of the pulses, whilst offering maximum diversity and a unit rate. The invention also relates to a pulse UWB transmitter system with 2, 4, or 8 antennas which uses this differential space-time coding, as well as an associated receiver system which does not require channel estimation.

Abstract: The invention relates to a space-time coding method for a MIMO-UWB system with P antennas using information symbols belonging to an M-PPM, where M is a multiple of P. The modulation alphabet is partitioned into P sub-alphabets corresponding to successive ranges of modulation positions. An extension of the initial alphabet is obtained by forcing the information symbols to belong to some sub-alphabets, thereby increasing the binary rate of said system.

Abstract: This invention relates to a space-time coding process for a pulse type MIMO-UWB system using symbols belonging to a PPM modulation alphabet. Orthogonality of signals emitted by the different antennas is achieved by providing a mechanism for permutation of PPM symbol modulation positions and by imposing a constraint on the positions of said symbols. The space-time coding process according to the invention enables an incoherent type reception.

Abstract: A space-time coding method for a UWB pulse type transmission/reception system. The space-time code, given for P=2, 4 or 8 transmission antennas, makes it possible to code 2-PPM information symbols and to modulate the position of UWB pulse signals using coded symbols, without requiring extension of the modulation alphabet. The space-time code is real with maximum diversity, and is full speed. The space-time decoding method is capable of estimating the information symbols thus transmitted.

Abstract: The present invention concerns a sphere decoder for maximum likelihood receiver intended to receive M-PPM-M?-PAM symbols at M modulation positions and at M? amplitude levels from a plurality P of sources. The sphere decoder uses a Schnorr-Euchner type enumeration adapted to classify the points of a multidimensional PPM-PAM modulation.

Abstract: The present invention concerns a sphere decoder for a maximum likelihood receiver intended to receive PPM symbols at M modulation positions from a plurality P of sources. The sphere decoder uses a Schnorr-Euchner type enumeration adapted to classify the points of a multidimensional PPM modulation.

Abstract: This invention relates to a cooperation procedure between terminals in a UWB pulse telecommunications system. A source terminal transmits a data symbol for a recipient terminal in the form of a signal, called a source signal, constituted by a sequence of identical frames, each frame containing a pulse that is position-modulated by means of a PPM modulation alphabet. A relay terminal, receiving said source signal, detects a modulation position of a pulse in at least one frame of the signal received and transmits a relayed signal containing, in at least one predetermined subsequent frame of this signal, a pulse the position of which is obtained on the basis of the first position by a permutation of the PPM modulation alphabet.

Abstract: This invention relates to a distributed space-time coding method for a UWB pulse telecommunication system wherein a source terminal transmits a signal to a destination terminal during a transmission interval constituted by K frames, K?1, each frame being divided into a first and a second half-frame, the signal transmitted in each first half-frame being received, then retransmitted after amplification during the next second half-frame by a distinct relay terminal among K relay terminals of said system. The source terminal codes 4K data symbols belonging to a PPM modulation alphabet or a composite PPM-PAM modulation alphabet including a plurality of time positions, to provide a sequence of four transmission symbols per frame, said transmission symbols being obtained from 4K linear combinations of said data symbols using a plurality of coefficients belonging to a real algebraic extension of degree 2K of the field of rational numbers and, for one of said transmission symbols, a permutation of its PPM components.

Abstract: The invention relates to a learning process for an ultra wideband communication system with M transmission antennas and N reception antennas and in which the information is modulated on L possible positions comprising the following steps: a) transmit a series of Nseq learning pulses from each emission antenna to all reception antennas. b) for each reception antenna j, estimate the M composite responses of series of emitted pulses that arrive at this reception antenna j, each composite response being estimated by eliminating the effects of other antennas. c) estimate correlations between the different channels.