A method for air to ground uplink synchronization comprises initiating a downlink synchronization of user equipment onboard an aircraft with a ground base station; computing a range to the base station based on a downlink path loss; selecting an initial time advance (TA) value from a set of predetermined TA values based on the range; and sending a first random access channel (RACH) request with the initial TA value to the base station in a first attempt to synchronize an uplink signal and attach the user equipment to a network. If the user equipment fails to attach, a next RACH request is sent with a next TA value to the base station, in a next attempt to synchronize the uplink signal and attach the user equipment to the network. If the user equipment fails again to attach, the method is repeated until the user equipment is attached to the network.
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