Patent ID: 8687726

Claim:
A method for transmitting digital data over a communication channel, between: a transmitter base comprising transmission antennas of index n, where n is between 1 and N and N is an integer greater than 1, and receivers of index k, where k is between 1 and K and K is an integer greater than 1, each receiver comprising at least one receiving antenna, wherein a signal carrier of frequency f 0 is used to transport the digital data on the communication channel, and sub-carriers are used of index m, where m is between 1 and M, and M is an integer greater than 1, adapted to transport K streams of digital data s k in parallel from the transmitter base, each stream of digital data s k being intended for each receiver of index k, wherein said method comprises the following steps: (a1) each of the K streams of digital data s k are transformed into M parallel streams s k (m) of symbols, each of the parallel streams being intended for a sub-carrier of index m, (b1) N.M complex symbols t n (m) are calculated from the K.M symbols s k (m), by: t n â¡ ( m ) = âˆ‘ k = 1 K â¢ Î± k Â· H k , n * â¡ ( m ) Â· s k â¡ ( m ) where * denotes a complex conjugate, H k,n (m) is a complex value estimating the transfer function of the communication channel between the transmission antenna n and the at least one receiving antenna k at a corresponding frequency of the sub-carrier m, and a k is a normalization coefficient, adapted to avoid obtaining complex symbols t n (m) of too large a value which would cause saturation, (c1) N multi-carrier modulations of the complex symbols t n (m) are performed, where said m is between 1 and M, to produce N transmission signals v n (t), each transmission signal v n (t) being intended for the transmission antenna n, and all the multi-carrier modulations being synchronous with each other, and (d1) each transmission signal v n (t) in the communication channel is transmitted by the transmitter base.