Patent ID: 8194775

Claim:
Method of differential space-time coding for a ultra-wide band (UWB) transmitter system with two radiative elements where said method codes a block σ k =(S k,1 , s k,2 ) of information symbols which belong to a double pulse position modulation (2-PPM) modulation alphabet, into a sequence of two vectors with two components, the components of a vector being intended to position modulate a pulse UWB signal for a given radiative element of the said system and a given transmission channel use, each component corresponding to one pulse position modulation (PPM) modulation position, characterised in that said vectors are obtained from elements of the code matrix: C k = ( c k , 1 c k , 2 c k , 2 ⁢ Ω c k , 1 ) where C k =sgn(C k o −[Min(C k o ){circle around (x)}u 1 ]), C k o =C k−1 S k , u 1 =(1 1), {circle around (x)} is the Kronecker product, sgn (X) is the matrix which gives the sign values of the elements of X , the sign value being respectively equal to −1,0,1 if the element is negative, of null value or positive, Min (X) is a matrix whose elements give the lower values of two consecutive elements of a row of the matrix X, C k−1 is the code matrix for the previous block of information symbols and S k = ( s k , 1 s k , 2 s k , 1 ⁢ Ω s k , 2 ⁢ Ω s k , 2 ⁢ Ω s k , 1 s k , 2 s k , 1 ⁢ Ω ) a row of the matrix C k corresponding to a use of the transmission channel and a column of the matrix corresponding to a radiative element, where the matrix C k is defined to within a permutation of its rows and/or its columns and Ω being a permutation of the two PPM modulation positions.