Performance analysis of slotted replication Aloha over fading communications channels

The average throughput, average delay, and the first exit time performances are determined for a slotted two-packet replication Aloha protocol in a fading communications channel environment using a two-state Gilbert (1960) channel error model with memory. Comparison to slotted Aloha without replication shows that a smaller total average delay can be achieved by using two-packet replication. Average throughput is improved in some cases. However replication reduces the stability of the system. The Markov model for the slotted replication Aloha system is discussed, and the stability is quantified in terms of the expected first exit time from the safe channel operating region