D - 7382 Chapter 2 Multiple Access Trade Study

The Personal Access Satellite System (PASS) strawman design, as described in the PASS Concept Study Report, (hereafter referred to as the Strawman Design) utilizes a hybrid Time Division Multiple Access (TDMA)/ Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). In the forward direction each transponder has a narrow band pilot channel plus two relatively high rate data and voice channels. In the return direction, access to the system by users is provided using narrow band Single Channel Per Carrier (SCPC), frequency division, Demand Assigned Multiple Access (DAMA). The channel assignment is done by a Network Management Center (NMC).