Certain aspects of the present disclosure provide techniques for determining when to transmit and transmitting an aperiodic tracking reference signal (TRS). Certain aspects provide a method for wireless communication. The method generally includes determining a channel condition change of a downlink channel between a first wireless device and a second wireless device. The method further includes determining whether the channel condition change satisfies a trigger condition. The method further includes triggering transmission of an aperiodic tracking reference signal when the channel condition change satisfies the trigger condition.