Methods, systems, and devices for wireless communication are described. A base station may multiplex reference signal (RS) transmissions for different antenna ports over a set of resource elements using a code division multiplexing (CDM) group spreading in a time dimension and a frequency dimension. The base station may transmit the RS transmissions over the set of resource elements based at least in part on the multiplexing to a user equipment (UE). The UE may demultiplex the RS transmissions based at least in part on a CDM group and may select at least one of the time dimension or the frequency dimension over which to demultiplex the RS transmissions based on a determination or other information.