In a communication system transmitting from multiple antennas to multiple users, data transmission rates are allocated over scheduled users by varying the weights assigned to the users. The user weights determine the transmission precoding vectors used for the transmissions, which determine the data rates. In one embodiment, a set of predetermined weights is selected from a plurality of sets of weights as the one maximizing the sum, over all scheduled users, of the ratio of each user's instantaneous data rate to the average rate over prior frames. In another embodiment, the weights, precoding vectors, and data rates are frequency-specific. In another embodiment, the user weights are determined through an iterative process of assigning initial weights, determining the precoding vectors associated with the weights, determining the channel conditions for transmission using the determined precoding vectors, and adjusting the user weights based on their relative channel conditions.