Digital audio broadcasting with satellites and supplementary terrestrial transmitters-code division vs. time division

The FCC has authorized two licensees for the digital audio radio service. We consider the relative merits of code division multiplexing (CDM) and time division multiplexing (TDM) for this use. It is assumed that two satellites would be used to cover CONUS to supply diversity as well as multiple same-frequency terrestrial transmitters in selected urban areas. Initially we consider systems with no polarization reuse but then show the improvement that polarization reuse and other techniques to isolate transmission paths brings. But this brings the added expense of multiple down converters. We demonstrate an innovative technique that can eliminate the expense of multiple converters.