Method and a device for determining shifting parameters to be used by at least a first and a second telecommunication devices

Device for determining shifting parameters p1 and p2 to be used by a first and a second telecommunication devices for mapping symbols on sub-carriers, the first telecommunication device comprising at least two transmit antennas, the symbols being transferred through each antenna of the first telecommunication device on at least an even number ‘M1’, strictly greater than two, of sub-carriers allocated to the first telecommunication device, the second telecommunication device comprising at least two transmit antennas, the symbols being transferred through each antenna of the second telecommunication device on an even number ‘M2’, equal or greater than M1, of sub-carriers allocated to the second telecommunication device,

• the first telecommunication device transferring on a first antenna of the first telecommunication device during a time slot on each frequency ‘k1’, with k1=0 to M1−1, a signal representing a symbol ‘Xk1’ in the frequency domain,
• the first telecommunication device transferring on a second antenna of the first telecommunication device during the time slot, on each frequency ‘k1’, with k1=0 to M1−1, a signal representing a symbol ‘X′k1’ derived from the symbol Xk1, for each frequency k1, by the formula X′secondAntk1=ε(−1)k1+1X*(p1-1-k1)modM1, where ε is 1 or −1, X* means the complex conjugate of X, p1−1-k1 is taken modulo M1 and p1 is even,
• the second telecommunication device transferring on a first antenna of the second telecommunication device during a given time slot on each frequency ‘k2’, with k2=0 to M2−1, a signal representing a symbol ‘Yk1’ in the frequency domain,
• the second telecommunication device transferring on a second antenna of the second telecommunication device during the same time slot, on each frequency ‘k2’, with k2=0 to M2−1, a signal representing a symbol ‘Y′k2’ derived from the symbol Yk2, for each frequency k2, by the formula Y′secondAntk2=ε(−1)k2+1Y*(p2-1-k2)modM2 where p2−1-k2 is taken modulo M2 and p2 is even,
• the device for determining shifting parameters comprises:
• means for allocating to the first and the second telecommunication devices sub-carriers, at least a part of the sub-carriers allocated to the first telecommunication device being allocated to the second telecommunication device,
• means for determining the shifting parameter p1, the shifting parameter p2 being even and at least equal to the number of overlapping sub-carriers allocated to both the first and the second telecommunication devices or the shifting parameter p2 being even and at most equal to M2 minus the number of overlapping sub-carriers allocated to both the first and the second telecommunication devices.