Certain aspects of the present disclosure relate to methods and apparatus for receiving ACK/NACK reporting in unlicensed IoT systems with long transmission durations. In one example, an eNodeB executes an LBT protocol to gain access to a channel of a shared spectrum, receives radio resource management (RRM) measurement reports from an IoT-U, estimates a number of repetitions used to schedule the IoT-U based on the RRM measurement, and configures the maximum number of HARQ processes that can be scheduled in a frame based on the RRM measurements and the estimate of the repetitions.