A transmitter that has a plurality of antenna elements and executes spatially multiplexed transmission of data to a receiver via the antenna elements, where the data is weighted utilizing a transmission weight. Channel state information, which indicates propagation characteristics between the antenna elements and an antenna element of the receiver, is obtained or estimated. When the channel state information has been updated, an updated transmission weight is computed based on the previous channel state information before the updating thereof and/or the updated channel state information, and the previous transmission weight before the updating thereof, which was computed for the previous channel state information.