Disclosed herein are methods and systems for scheduling transmission of uplink communication. One embodiment takes the form of a process carried out by a first-radio-access-network-(RAN) entity in a first RAN, where the first RAN has a first-RAN uplink that is time-synchronized with a second-RAN uplink of a second RAN. The first-RAN entity detects an uplink-scheduling event associated with a mobile radio, and the first-RAN entity also identifies a second-RAN-uplink-transmission time slot for the mobile radio. The first-RAN entity schedules the mobile radio to transmit first-RAN-uplink communication, which is associated with the detected uplink-scheduling event, during a first-RAN-uplink time slot that does not overlap the identified second-RAN-uplink-transmission time slot.