Adaptive two-tier energy-efficient multicasting in mobile and wireless ad hoc networks

In this paper, we study the problem of energy-efficient multicasting in mobile and wireless ad hoc networks. To deal with node mobility, we present a two-tier multicasting model which consists of mobile nodes and stationary nodes. Mobile nodes achieve multicasting through the closest stationary node at lower tier. Stationary nodes route the messages via a multicast tree at higher tier. We find that the energy-efficiency of the multicast tree at higher tier is only dependent upon the aggregate traffic at the stationary nodes. In other words, both node mobility at lower tier and variance of group membership are mapped as dynamic Multicast Traffic Distribution (MTD) at higher tier. To achieve energy-efficiency multicasting, we propose a distributed algorithm T-REMiT which adapts to MTD through local refinements and allows simultaneous refinements. Our NS-2 simulation results show that T-REMiT not only outperforms other proposed algorithms (such as BIP/MIP and EWMA) when MTD is static, but also can achieve energy-efficient multicasting by adapting to the dynamic MTD. We also find that the overhead of T-REMiT is negligible compared with the energy gain in the adaptation