A cross-layer design for passive forwarding node selection in wireless ad hoc networks

In this paper, we propose a cross layer design concept that improves network performances in terms of delay and throughput by minimizing control overhead packets in wireless ad hoc network. The design is based on the observation that when a shared-channel wireless network has sufficient number of nodes only a few of them need to participate in packet forwarding operation in order to maintain active connections of the network. A hierarchy among the network nodes is created by classifying network nodes as mobile node (MN) and forwarding node (MN). FNs route the packets and MNs host the applications. A FN selection algorithm is presented in this paper which is based on the information content in on demand route discovery packet and the lower layer channel information such as contention level estimation at the medium access control (MAC) layer. Such provision of forming hierarchy among network nodes significantly reduces overhead control packets and hence improve network performances. We modify dynamic source routing (DSK) protocol to implement our algorithm called hierarchical dynamic source routing (HDSR) by a network simulator (network simulator-2 of University of California). Our simulation results show HDSR reduces control overhead packets per data packet and average delay per data packet up to 85% and 50% respectively.