Certain aspects of the present disclosure relate to a technique for managing contention-based uplink data transmissions. According to certain aspects, a base station may allocate a common contention-based resource to a plurality of user equipment (UEs). The plurality of UEs may utilize the contention-based resource to transmit uplink data without prior scheduling, which may result in transmission collisions. Certain aspects of the present disclosure provide a mechanism for determining which UE sent an uplink transmissions based on one or more transmission parameter signaled to the UEs.