Enhanced Geographic Routing with Two-Hop Neighborhood Information in Sparse MANETs

The advance of wireless and mobile communications and networking technologies enables networked nodes to transmit and receive data in ad hoc manners without resorting to dedicated network infrastructures. When nodes arbitrarily move in a geographic area, they carry data and attempt to exchange data during encountering each other in one-hop or multi-hop transmission range. Such a basic data delivery model is practical in many emerging application environments, like disaster, military and rural fields, etc., which turns out to be the research of routing in sparse mobile ad hoc networks (MANET). In sparse MANETs with lower node population or node density relatively, the performance of data delivery is highly affected by communication voids that arise from unpredictable transmission failure while no neighbors exist in mutual transmission ranges. This paper proposes a new geographic routing scheme to deal with critical communication voids in sparse MANETs. The proposed scheme exploits the geographic location and two-hop neighborhood information, and then devises a forwarding node selection policy for determining appropriate relay candidates that move towards target nodes in a network. To this end, this geographic routing scheme is able to reduce transmission overhead and end-to-end delay against communication voids in infrastructure-less environments. In addition, this paper examines the proposed scheme using synthetic studies on a dedicated opportunistic networking simulator. Simulated results show that this scheme obtains considerable performance in terms of successful delivery ratio and transmission overhead under the random waypoint mobility models in synthetic contexts of sparse MANETs.