A spatial spreading unit is configured to utilize a spatial spreading matrix to distribute two or more encoded spatial data streams to transmission antennas. The spatial spreading matrix has components (i) associated with each row of a row dimension having a number of rows equal to the number of the transmission antennas to be used to transmit the encoded spatial data streams and (ii) associated with each column of a column dimension having a number of columns equal to the number of the encoded spatial data streams to be transmitted. Additionally, the spatial spreading matrix satisfies one or more of the following two constraints: (1) the ratio of squared norms of the sum of the components of a row, for different rows of the spatial spreading matrix, is equal to a first constant sequence, and (2) the ratio of squared norms of the sum of a symbol Sl to be transmitted, when the symbol Sl is equal to 1 or −1, multiplied by each of the components of a row, for different rows of the spatial spreading matrix, is equal to a second constant sequence.