A mobile station in a communications system includes hardware and software stored on a tangible computer readable medium that, during operation, cause the mobile station to receive a timeslot assignment from a wireless network and operate based on the received timeslot assignment. The timeslot assignment may be based on whether a timing advance offset is used by the wireless network. The mobile station may also receive an indication from the wireless network, indicating whether a timing advance offset is used by the wireless network. The mobile station may subsequently operate based on the received indication.