Epidemic theory based H + 1 hop forwarding for intermittently connected mobile Ad Hoc networks

In intermittently connected mobile Ad Hoc networks, how to guarantee the packet delivery ratio and reduce the transmission delay has become the new challenge for the researchers. Epidemic-theory based routing has shown the better performance in terms of improving packet delivery ratio and reducing the delay, when infinite node buffer and network bandwidth model is assumed. Typically, epidemic routing adopts the 2-hop or multi-hop forwarding mode to deliver a packet. However, these two modes have the intrinsic disadvantage on too much redundant copies or too long delivery delay. In this paper, we introduce a novel H+1 hop forwarding mode that is based on the epidemic theory. Firstly, we utilize the Susceptible-Infective-Recovered (SIR) model of epidemic theory to estimate the amount of relay nodes (epidemic equilibrium) and the delivery delay within the epidemic process. Secondly, we formulate the quantities of relay nodes into a single absorbing Markov Chain model, facilitating the estimation of the expected delay for the packet transmission. Simulation results show that our H+1 hop forwarding mode has the better performance on delay and packet delivery ratio.