A COMPARISON OF 2 MULTIPLE ACCESS SCHEMES FOR SATELLITE NETWORKS WITH ERROR-PRONE TRANSMISSION CHANNELS

Multiple access to the radio channel is an important feature for the efficiency of satellite packet data networks. In the case of mobile stations communicating via satellite, which is the scope of this paper, the performance of the various channel access methods is degraded by transmission errors due to multipath propagation and signal shadowing. Using the same channel and user models and the same method of analysis, the performance of two typical access schemes from different classes is compared: Slotted Aloha and a demand assignment (DAMA) technique. Slotted Aloha exhibits less delay than DAMA for a moderate data traffic, but DAMA supports more data traffic when the link quality is good. Under the influence of shadowing on the channel, Slotted Aloha degrades more slowly than DAMA due to the capture-effect.