Sounding reference signal (SRS) transmission with implied request-to-send (RTS)/clear-to-send (CTS) operations is discussed. Two different types of SRS are defined, a legacy SRS associated with channel measurement sounding, and a contention SRS associated with contention resolution for medium sharing. The type of SRS may be distinguished based on the SRS resource associated with the particular type. Thus, legacy SRS are assigned to one SRS resource, while contention SRS are assigned to separate SRS resources. Therefore, when a neighbor node detects an SRS associated with the SRS resource for contention-type SRS, the neighbor node may know to refrain from transmission or to adjust or modify its communications depending on a spatial direction of the contention SRS.