Broadcast Modeling and Rate Optimization for Ad Hoc Networks Using Epidemic Theory

Broadcast plays a vital role in wireless ad hoc networks for information dissemination, while one of the key system parameters for maximizing broadcast performance is the transmission rate. However, due to the entangled impact of various factors on the broadcast performance such as node distribution, interference, transmission rate, and multi-hop links, theoretically modeling of the impact of different parameters on the broadcast performance is intractable, and hence the optimal transmission rate is still unknown. Inspired by the similarity between the process of packet broadcasting and the spreading of contagious diseases, we resort to epidemic theory to propose a tractable approach for modeling the dynamics of message broadcast process in wireless ad hoc networks. To characterize the impact of transmission rate on the broadcast performance, a novel utility function is proposed by jointly considering the packet delivery delay and packet size. Then, we derive the dynamics of packet broadcasting analytically and obtain the approximated expression for the proposed utility function in closed-form. Furthermore, the optimization of the transmission rate is carried out based on our proposed analytical model. Simulation results show that our analytical model can accurately characterize the process of broadcasting under a wide range of system parameters and that optimizing the transmission rate can improve broadcast performance significantly.