Patent ID: 8477869

Claim:
An apparatus, comprising: a symbol encoder unit to produce two or more encoded spatial data streams, wherein a number, N SS , of the encoded spatial data streams is less than a number, N TX , of transmission antennas to be used to transmit the encoded spatial data streams; and a spatial spreading unit to utilize a spatial spreading matrix Q to distribute the two or more encoded spatial data streams to the transmission antennas, wherein: Q has N TX , rows and N SS , columns, Q satisfies one or more of the following two constraints:  ∑ l = 1 N SS ⁢ Q ⁡ ( t , l )  2 = A t ⁢ B ( a ) for all t=1 . . . N TX , or  ∑ l = 1 N SS ⁢ S l ⁢ Q ⁡ ( t , l )  2 = A t ⁢ B ( b ) for all t=1 . . . N TX when S l is equal to (i) 1 or (ii)−1, Q(t,l) is a component of Q at row t, column l, S l is a symbol in an 1-th spatial stream, B is a constant, and A 1 , A 2 , . . . , A N TX is a sequence of constants designed, when at least some power amplifiers corresponding to the N TX transmission antennas have different operating regions, based on the linear operating regions of the power amplifiers.