Patent ID: 7974359

Claim:
A method for transmitting a number of streams of modulation symbols by a multi-antenna transmitter in a wireless communication network, the method comprising: transforming a first number (N 1 ) of streams of modulation symbols to a second number (N 2 ) of streams of symbols, N 1 being smaller than N 2 ; and transmitting the second number of streams of symbols by a transmitter comprising N 2 antennas, wherein said transforming includes operating on the first number of streams of modulation symbols by a vector rotation operation, wherein the vector rotation operation includes a discrete Fourier transformation, and wherein said operating includes operating the discrete Fourier transformation, represented by a unitary square matrix of a dimension equal to N 2 , on the first number of streams of modulation symbols after being augmented by a third number (N 3 ) of known pilots; wherein said unitary square matrix is defined by: ⁢ D = 1 N T ⁢ [ 1 1 1 ⋯ 1 1 e j 2 ⁢ π N T e j 2 ⁢ π N T · 2 1 e j 2 ⁢ π N T · 2 e j 2 ⁢ π N T · 2 · 2 ⋮ ⁢ d P ⁢ , q = e j 2 ⁢ π N T ⁡ ( P - 1 ) ⁢ ( q - 1 ) ⁢ 1 ⋱ ⁢ ⁢ e j 2 ⁢ π N T ⁡ ( N T - 1 ) 2 ] ⁢ N T × N T .