In a general aspect, a rate at which MIMO transmissions are elicited from wireless communication devices is varied. A first wireless communication device may be configured to wirelessly transmit a first set of messages at a first transmission rate to a second wireless communication device. The first wireless communication device may further be configured to receive MIMO transmissions from the second wireless communication device. The first wireless communication device may additionally be configured to generate first channel information based on respective training fields in each of the first MIMO transmissions; determine a rate at which the first channel information is generated; vary the first transmission rate to a second, different transmission rate based on the rate at which the first channel information is generated; and wirelessly transmit a second set of messages at the second transmission rate to the second wireless communication device.