Provided herein are various improvements to communication systems and satellite-carried communications. In one example, a method provides communication coverage for at least an endpoint device within a cell. The method includes detecting access preamble communications transferred by the endpoint device during a random access slot of a base station by at least applying a selected quantity of successive sets of processing windows in accordance with a round-trip minimum communication delay expected between the base station and the cell, with each of the successive sets shifted in time by a selected duration. The method also includes determining a round-trip differential communication delay for the endpoint device based on which of the successive sets corresponds to detection of symbol groups of the access preamble communications, and handling return communications transferred by the endpoint device based at least on a combination of the round-trip minimum communication delay and the round-trip differential communication delay.