Patent ID: 7986743

Claim:
A method for transmitting a digital data stream, comprising: mapping the data stream to a plurality of modulation symbols wherein; each modulation symbol is associated with a subcarrier of a multiplicity of subcarriers; the multiplicity of subcarriers comprises at least a first plurality of subcarriers and a second plurality of subcarriers; the subcarriers of the first plurality of subcarriers have different frequency and are sent by a first antenna and each modulation symbol that is associated with a subcarrier of the first plurality of subcarriers is also associated with the first antenna and; the subcarriers of the second plurality of subcarriers have different frequency and are sent by a second antenna and each modulation symbol that is associated with a subcarrier of the second plurality of subcarriers is also associated with the second antenna; wherein the modulation symbols are grouped into at least one block; transforming the modulation symbols such that a multiplicity of transformed modulation symbols is formed from the modulation symbols wherein; at least two modulation symbols associated with sub-carriers having different frequency are and associated with a same antenna are linearly combined to form a transformed modulation symbol according to a multiplication of a block of modulation symbols by a first transformation matrix; and at least one modulation symbol associated with the first antenna and at least one modulation symbol associated with the second antenna are linearly combined to form a transformed modulation symbol according to a multiplication of a block of modulation symbols by a second transform matrix; and each transformed modulation symbol is associated with a subcarrier; and using each transformed modulation symbol to modulate the subcarrier associated with the transformed modulation symbol, wherein OFDM modulation is carried out in between the processing by the multiplication of a block of modulation symbols by the first transform matrix and the processing by the multiplication of a block of modulation symbols by the second transform matrix.