A wireless communications system includes a space-based component (SBC) and an ancillary terrestrial component (ATC) configured to communicate with radioterminals using a common satellite service link frequency band and respective first and second different sets of channel separation codes. The first and second sets of channel separation codes may include, for example, respective sets of scrambling codes, respective sets of frequency assignment codes, respective sets of channel assignment codes, respective sets of sub-channel assignment codes and/or respective sets of spreading codes.