Patent ID: 7315530

Claim:
A method of pre-distorting a signal (S i (t)) to be transmitted over an uplink transmission channel to a base station by a mobile terminal (i), each symbol (d i ) transmitted by said mobile terminal being spread with a coding sequence (c i (l)) over a plurality of carriers (l) to produce a plurality of corresponding frequency components (d i c i (l)) of said signal (S i (t)), comprising: weighting each frequency component (d i c i (l)) by a weighting coefficient (ω i (l)) corresponding to one channel response coefficient (h i (l)), of a plurality of channel response coefficients, of a corresponding downlink transmission channel at a corresponding frequency (f l ) and to a value of a noise variance (σ 2 ) affecting said plurality of carriers, said step of weighting including, for said mobile terminal (i), determining a vector ω i representing said weighting coefficients from a vector h i representing said channel response coefficients as a conjugate of a vector ω i , vector ω i being w i = α ⁡ ( Φ i + σ 2 N ⁢ I ) - 1 ⁢ h i , where I is the identity matrix, N is a length of said coding sequence, α is a normalisation factor, and Φ i is a matrix depending on coding sequences allocated to active mobile terminals served by said base station and depending on said channel response coefficients.