Patent ID: 7173976

Claim:
A transmitter comprising: two antennas for transmitting information to a receiver via a transmission medium of memory Î½; and an encoder handling two blocks of incoming symbols at a time, each block containing N of said incoming symbols, and encoding said N blocks of incoming symbols into two streams of symbols in pairs of output frames k and k+1, yielding output frames x i k and x i k+1 , for i=1, and 2, where each of a the frames includes Î½ prefix symbols, each being applied to a different one of said two antennas, where said encoding involves modulo arithmetic, and wherein frame k said encoder generates a stream of symbols, x 1 k (n), n=0, 1, 2, . . . Nâˆ’1, that is applied to a first one of said antennas, preceded by a cyclic prefix sequence of symbols to form a steam of symbols x 1 k (âˆ’Î½);x 1 k (âˆ’Î½+1), . . . ,x 1 k (0),x 1 k (1), . . . ,x 1 k (Nâˆ’1) where Î½ equals to symbol memory of channel through which said transmitter communicates with a receiver, where a cyclic prefix sequence is one where x 1 k (i) in the prefix sequence equals x 1 k (Nâˆ’i) in the succeeding sequence, and a stream of symbols, x 2 k (n), n=0, 1, 2, . . . Nâˆ’1, that is applied to a second one of said antennas, preceded by a cyclic prefix sequence of symbols to form a steam of symbols x 2 k (âˆ’Î½),x 2 k (âˆ’Î½+1), . . . ,x 2 k (0), x 2 k (1), . . . ,x 2 k (Nâˆ’1) and in frame k+1 said encoder generates a stream of symbols x 1 k+1 (t) that is equal to âˆ’ x 2 k ((âˆ’n) N ), that is applied to said first one of said antennas, preceded by a cyclic prefix sequence of symbols to form a steam of symbols x 1 k+1 (âˆ’Î½), x t k+1 (âˆ’Î½+1), . . . ,x 1 k+1 (0), x t k+1 (1), . . . ,x 1 k+1 (Nâˆ’1), and a second stream of symbols x 2 k+1 (t) that is equal to, x 1 k ((âˆ’n), that is applied to said second one of said antennas, preceded by a cyclic prefix sequence of symbols to form a steam of symbols x 2 k+1 (âˆ’Î½),x 2 k+1 (âˆ’Î½+1), . . . ,x 2 k+1 (0),x 2 k+1 (1), . . . ,x 2 k+1 (Nâˆ’1).