An efficient narrowband UHF DAMA protocol and waveform developed for USTS

The UHF satellite terminal system (USTS) introduces a demand assigned multiple access (DAMA) scheme for efficient sharing of a 5 kHz UHF satellite communication broadcast channel among a large number of users. The 5 kHz UHF DAMA protocols offer simplicity while providing both packet and virtual circuit type services, multiple precedence levels, message acknowledgements, variable-size message packets, several over-the-air burst rates, and multiple-hop routing for global connectivity. The protocols and the UHF waveform developed for the USTS have been used as the basis for a US Department of Defense 5 kHz DAMA waveform standard. The protocols and the waveform are described, and message delay performance simulation results are presented. The analyzed performance indicates that a network shared by 250 users with a typical distribution of link qualities and an aggregate throughput of 1350 messages per hour will operate at 63% efficiency