Disclosed are techniques for determining tone patterns and associated overlay codes for transmission of reference signals. A tone pattern (e.g., with each tone pattern occupying a resource element in a resource block) can be determined for a reference signal for use in wireless communications between a receiving device and a transmitting device. The tone pattern can include an irregular combination of resource elements in one or more resource blocks for the reference signal. The resource elements can be shared by a plurality of antennas for communication of one or more reference signals between at least the user equipment and the base station. An overlay code may be determined for the tone pattern. Information associated with the transmission of the reference signal using the tone pattern and the overlay code may be communicated by the receiving device.