Methods, systems, and devices for wireless communication are described. A network device, such as a base station, may transmit a request message to a user equipment (UE). The request message may include a request for the UE to transmit a set of sounding reference signals (SRSs). The set of SRSs may include two (or more) beamformed signals. The network device may receive the set of SRSs according to the request message. The network device may identify, based on a co-phasing parameter associated with the two (or more) beamformed signals, an antenna port precoder configuration to use for communicating with the UE.