Delay bounds for packet satellite protocols

Two very simple and very tight lower bounds on average delay are derived for packet satellite protocols with contention-free and contention-based control channels. The derivation indicates that, for minimum delay, a protocol should maintain a balance between transmitting packets immediately and making reservations before transmissions. In addition, whenever possible, all unreserved slots should be filled with new transmissions at a rate of one packet per slot. For a small number of users, TDMA (time division multiple access) may be a better alternative than contention-based protocols. The exact conditions on the number of users and system throughput for selecting either protocol are also derived.<>