Differentiated probabilistic forwarding for extending the lifetime of opportunistic networks

Probabilistic forwarding methods have been exploited in opportunistic networks to reduce the overhead of epidemic routing. However, most existing methods make all the nodes forward messages with the same probability (i.e., equal scheme), which causes the energy unbalance of nodes. To guarantee the energy balance of nodes and prolong the network lifetime, we design a differentiated scheme, i.e., different nodes are assigned with different forwarding probabilities based on their respective energies. We model the message dissemination based on the differentiated scheme, and formulate two optimization problems: maximize the message deliver probability under the constraint on the total energy consumption, and based on this, maximize the network lifetime under the constraint on the energy consumption of each node. By solving these two optimization problems, we derive the optimal differentiated forwarding probabilities by theoretical analysis. Our simulation results show that our designed differentiated scheme can guarantee the message deliver probability and extend the network lifetime, compared with the equal scheme.