SIMULATION OF SPREAD SLOTTED ALOHA FOR MOBILE . SATELLITE COMMUNICATION

Abstract

Mobile and personal satellite communication systems are usually characterized by low power transmission, simple receiver structures, severe propagation losses, large population of users, relatively lower duty cycle traffic and timing synchronization (e.g., time of packet arrival). Developing networking techniques, particularly hybrid concepts to suit these characteristics, are essential. The objective of this thesis is to study Spread Slotted ALOHA (SSA) techniques which combine certain characteristics of both spread spectrum systems and slotted ALOHA (SA) systems to achieve better performance than the constituent systems. Our second objective is to improve the performance of Spread Slotted ALOHA using forward error correction. . Our results demonstrate that SSA offers significant improvements in terms of throughput, delay, and network stability against excessive loading at very acceptable levels of receiver complexities. From our second objective we also show that using FEC throughput performance can further be improved when compared to uncoded systems under heavy traffic conditions.