| 主权项 |
1. A method of transmitting data to user equipments in a communication network, the method comprising:
receiving a non-acknowledgement message, comprising a difference of preferred matrix indices information, indicating that a data packet precoded by using a first matrix and transmitted a first time by using a cooperative transmission scheme is not decoded correctly, where the cooperative transmission scheme is performed by a central unit performing a common signal precoding wherein a matrix multiplication is performed of all data signals to be transmitted to all cooperating user equipments with a precoding matrix; determining a second matrix using the preferred matrix indices information; preparing a recoded data packet by precoding the data packet using the second matrix, wherein the second matrix is different from the first matrix, wherein in the preparing of the recoded data packet a scaling factor is taken into account,
wherein the scaling factor is adapted to compensate for the channel evolving between the first transmission and the retransmission,wherein the scaling factor is determined by SC=Tx(t3)/ΔW*Hdelayd,wherein Tx(t3) corresponds to the relative overall transmit power at the time point of transmitting the recoded data packet,wherein ΔW is a difference precoding matrix, calculated by ΔW=W(t2)−W(t1),wherein W(t1) represents the first matrix used for precoding, while W(t2) represents the precoding matrix corresponding to the channel matrix H at the time point of the first transmission,wherein Hdelay corresponds to the channel matrix at the time (t2) of the first transmission, and d represents the data packets, andwherein the second matrix is based on a time corrected channel matrix which considers the evolution of the channel over a time period between calculating the first matrix and the first transmission; and retransmitting the recoded data packet. |
