Effect of Exponential Backoff on the Performance of Network Coding in a Slotted Aloha Network

In this paper we study the effect of exponential backoff on the performance of network coding in a simple ad hoc network working based on slotted Aloha. To this end, we devise an analytical model based on an open multi-class queueing network to represent our scenario. In this model, by mapping backoff status of packet transmissions onto suitable classes of customers on one hand, and employing two previously introduced modeling principles to represent packet combination and packet multicasting, needed in network coding scenarios, on the other hand, we are able to find the maximum stable throughput, i.e., the maximum packet arrival rate at which the queueing nodes remain stable. We observe that exponential backoff may reduce the amount of superiority of network coding to simple routing. Finally, we confirm our analytical model by some simulations. Keywords— Network coding, slotted Aloha, exponential backoff, queueing network.