Patent ID: 8068462

Claim:
A method for retransmitting data based on antenna scheduling in a MIMO system to which a spatial multiplexing technique is applied, the method comprising the steps of: (a) at a transmitter side, modulating an input packet into transmittable data to transmit to a receiver side; (b) at the receiver side, estimating channel values from the packet transmitted from the transmitter side, calculating channel sums or channel norms from the channel values, and selecting a predetermined number of transmitting and receiving antennas in magnitude order of the channel sums or channel norms, wherein the channel sums are calculated by the following equations: CHSum T j = ∑ m = 1 N R ⁢ ⁢  H mj  , j = 1 , 2 , … ⁢ , N T , ⁢ and CHSsum R i = ∑ n = 1 N T ⁢ ⁢  H in  , i = 1 , 2 , … ⁢ , N R , where CHSum T j represents the channel sum of a j th transmitting antenna, CHSsum R i represents the channel sum of an i th receiving antenna, H represents a channel value estimated from the received packet, N T represents the number of transmitting antennas, and N R represents the number of receiving antennas; (c) detecting whether an error is present in the packet or not, and transmitting a feedback signal to the transmitter side, the feedback signal including information on whether or not to transmit the packet and a list of the selected transmitting antennas; and (d) at the transmitter side, retransmitting the transmitted packet or transmitting the next packet through the transmitting antennas designated by the receiver side depending on the feedback signal.