Patent ID: 7616703

Claim:
A method of achieving differential multiple-norm space-time transmit diversity from a unitary space-time modulation scheme using at least two transmit antennas in a differential multiple norm space-time diversity receiver, comprising the steps: dividing a group of transmission bits into a first sub-group of transmission bits and a second sub-group of transmission bits; mapping the first sub-group of transmission bits onto a constellation matrix of a differential unitary space-time modulation scheme; characterized by determining a scaling factor from the second sub-group of transmission bits; setting up a transmission matrix through differential encoding of the constellation matrix and a previously determined transmission matrix in combination with scaling by the scaling factor; wherein X k is the transmission matrix; X k−1 is the previously transmitted transmission matrix; C k is a constellation matrix of a differential unitary space-time modulation scheme; and k is a time index; and the scaling by the scaling factor comprises the steps determining an amplitude difference exponent qkε{−M 2 ÷1,−M 2 ÷2, . . . ,−1,0,1, . . . , M 2 −1 from the second subgroup of transmission bits; determining a scaling factor according to [a 9k ] 1/2 , wherein a is a predetermined constant; scaling the result of differential encoding of the constellation matrix and a previously determined transmission matrix with a scaling factor according to X k =[ a 9k ] 1/2 X k−1 C k .