Patent ID: 8059709

Claim:
Space-time coding method for an ultra wide band (UWB) transmission system comprising two radiation elements, said method comprising the steps of: coding a block of information symbols (S=(a 1 , a 2 , a 3 , a 4 )) belonging to a pulse position modulation (PPM) modulation constellation or a pulse position modulation-pulse amplitude modulation (PPM-PAM) composite modulation constellation with a number of time positions greater than or equal to 3, into a sequence of vectors (c 1 0 , c 2 0 , c 1 1 , c 2 1 the components of a vector being intended to modulate a UWB pulse signal for a radiation element of said system and for a given transmission interval (T f ), characterised in that a first and a second of said vectors are obtained by means of a first linear combination of a first and a second pair of said symbols, and in that a third and a fourth of said vectors are obtained by means of a second linear combination of said first and second pairs of said symbols, the first and the second linear combinations using scalar coefficients ({tilde over (Î±)}, {tilde over (Î²)}, âˆ’{tilde over (Î²)}, {tilde over (Î±)}), of which the corresponding ratios are approximately equal to the Golden number and to its opposite, the components of one of said vectors also being permuted according to a cyclic permutation prior to modulating said pulse UWB signal.