Patent ID: 8165194

Claim:
A space-time coding method for an Ultra Wide Band (UWB) transmission system comprising at least two radiative elements, said method comprising: coding a block of information symbols (S=(a 1 , a 2 . . . , a P 2 )) belonging to a 2-PPM (Pulse Position Modulation) modulation or 2-PPM-M′-PAM (Pulse Amplitude Modulation) composite modulation alphabet with M′≧2, into a sequence of vectors (s i,j ,Ωs i,j ), the components of a vector being intended to modulate a UWB pulse signal for a radiative element of said system and for a given transmission interval (T ƒ ), wherein said vectors are defined as the elements of the matrix: C = ( s 1 , 1 s 2 , 1 s 3 , 1 … s P , 1 Ω ⁢ ⁢ s P , 2 s 1 , 2 s 2 , 2 … s P - 1 , 2 ⋮ Ω ⁢ ⁢ s P , 3 s 1 , 3 ⋱ ⋮ Ω ⁢ ⁢ s 3 , P - 1 ⋱ ⋱ ⋱ s 2 , P - 1 Ω ⁢ ⁢ s 2 , P Ω ⁢ ⁢ s 3 , P … Ω ⁢ ⁢ s P , P s 1 , P ) defined to within one permutation of its lines and/or its columns, one line corresponding to a transmission interval and one column to a radiative element, wherein Ω is a ±π/2 rotation matrix, P is the number of radiative elements and s i , j = ( R j ⊗ I 2 ) ⁢ ( a ( i - 1 ) ⁢ P + 1 a ( i - 1 ) ⁢ P + P ⋮ a iP ) to within a ±10% margin, where I 2 is the identity matrix of size 2×2, is the tensor product, a l , l=1, . . . , P 2 are information symbols, R j is a line vector of dimension P corresponding to the j th line of an orthogonal matrix R generating the lattice of points Λ={uΘ|uεX P } with Θ = ( 1 θ 0 … θ 0 P - 1 1 θ 1 … θ 1 P - 1 ⋮ ⋮ … ⋮ 1 θ P - 1 … θ P - 1 P - 1 ) and wherein θ p , p=0, . . . , P−1 are P distinct real roots of a polynomial of degree P with rational coefficients.