Methods, systems, and devices for wireless communications are described. These wireless communications may include channel estimation procedures between communicating devices such as a base station and user equipment (UE). For example, the UE may receive, from the base station, a resource grant triggering a given reference signal configuration. Based at least in part on the type of reference signal configuration, the UE (e.g., and the base station) may determine a timing offset relative to the resource grant. The UE may transmit (and the base station may receive) the reference signal based at least in part on the timing offset. In some cases, the reference signal may be transmitted in a transmission opportunity of a set of transmission opportunities, where the set of transmission opportunities is determined based at least in part on the reference signal configuration.