Methods, systems, and devices for wireless communication are described, which may be employed for wireless communication in contention-based (e.g., unlicensed or shared) spectrum. An aperiodic channel state information (CSI) reference signals (RS) may be used for channel quality indicator (CQI) measurements, for example. A user equipment (UE) may receive signaling to indicate the presence of CSI RS and may receive the CSI RS according to the signaling. The UE may then compute a CQI based on CSI RS, and transmit the CQI in a report to a base station. In some examples, a quasi-periodic CSI RS is used. For instance, the UE may determine a different location for the CSI RS. For example, the UE may identify a periodic anchor subframe, and locate the CSI RS based on constant offset from the anchor subframe. Periodic or a clear-channel-assessment-exempt transmission based CSI RS examples are also described.