TR 90-66 by David H.C. Du, Subbarao Ghanta, Allalaghatta Pavan, and Leemay Yen Various protocols are employed to enable efficient use of the uplink and downlink channels in satellite communication systems. The most common ones are combinations of random access protocols with either TDM or demand assignment schemes. Addition of a small amount of control information in the data frames results in significantly increased capacities.
Stations announce their retransmission intent by transmitting control information in a minislot.
Conflicts between new transmissions and retransmissions and also those between retransmisions themselves can be compeltely avoided. The control subchannel overhead can be kept very low for large frame sizes in order to achieve comparable performance as that of the ARRA scheme. With a small extra overhead, dramatic improvements in capacity and delay over ARRA can be achieved. The proposed protocol provides significantly improved capacity over conventional protocols without compromising the simplicity and operational convenience of random access protocols. Also, because of delay considerations, the proposed protocol is particularly well suited for satellite channels.