Satellite Systems

Multiple Access

Since the Teledesic Network uses wireless access, communication channels are not dedicated to terminals on a permanent basis. The channel resources associated with a cell are shared among terminals in that cell, with capacity assigned on demand to meet their current needs. This flexibility allows Teledesic to handle efficiently a wide variety of user needs: from occasional use to full-time use; from bursty to constant bit-rate applications; from low-rate to high-rate data; from low usage-density areas to areas of relatively high usage density.

A multiple access scheme implemented within the terminals and the satellite serving the cell manages the sharing of channel resources among terminals. Within a cell, channel sharing is accomplished with

a combination of Multi-Frequency Time Division Multiple Access (MF-TDMA) on the uplink and Asynchronous Time Division Multiplexing Access (ATDMA) on the downlink.