Multi-Tier Mobile Ad Hoc Networks: Architecture, Protocols, and Performance

While mobile ad-hoc networking (MANET) research has received a considerable attention in recent years, the majority of them have focused on single-tier (e.g., ground) and homogeneous (e.g., same radio for every node) MANET. Few have investigated the potential implications of multi-tier and heterogeneous natures of MANET on the design and performance of MANET protocols in a systematic manner. For example, one of the stark differences between single-tier and multi-tier MANET environments is that the multi-tier MANET naturally creates “coverage asymmetry” due to the much larger coverage area by airborne nodes compared to ground nodes. Consequently, the number of “neighbors” an airborne node sees can be potentially several orders of magnitude larger than that of a ground node. Treating this airborne node same as any ground node will adversely affect the performance of medium access control (MAC) and/or routing MANET protocols. In this paper, we present a detailed multi-tier MANET architecture, associated issues, and protocols developed. Our novel protocols and simulation tools designed for multi-tier MANET are described with preliminary performance results. Keywords-mobile ad hoc networks; Multi-tier MANET; virtual dynamic backbone; Airborne Communication Node.