A technique may include controlling downlink transmission of an uplink grant for one or more uplink data transmissions by a communication device. The uplink grant identifies one combination from a set of predetermined combinations of one or more transmission time intervals and one or more uplink reference signal transmissions, including at least one combination of two or more transmission time intervals and one or more uplink reference signal transmissions. The technique may also include using the one or more uplink reference signal transmissions of the identified combination to assist the recovery of data from the one or more uplink radio data transmissions by the communication device in the one or more transmission time intervals of the identified combination.