The present invention concerns a method for transmitting symbols through at least a channel in a telecommunication system including at least one transmitter (10) provided with at least two transmitting antennas (Antt 1, Antt 2) and at least one receiver provided with at least one receiving antenna (Antr 1), the method includes an encoding step wherein a vector comprising symbols is multiplied by a coding matrix for producing coded symbols to be transmitted over the at least one communication channel established between the transmitter (10) and the receiver (20), wherein the coding matrix is calculated from an eigenvalue decomposition of a matrix obtained by calculating at least the Kronecker product of the identity matrix of size N, N being the time and/or the frequency dimension of the code and a matrix obtained from an estimated correlation matrix of the response of the channel. The invention concerns also the associated device and a method and device for decoding symbols.