Energy Efficient Node Caching and Load Balancing Enhancement of Reactive Ad Hoc Routing Protocols

Enhancing route request broadcasting protocols constitutes a substantial part of recent research in mobile ad-hoc network (MANET) routing. We suggest a novel approach to modify route request broadcast based on node caching. The intuition behind node caching is that the nodes involved in recent data packet forwarding have more reliable information about its neighbors and have better locations (e.g., on the intersection of several data routes) than other nodes. We cache nodes which are recently involved in data packet forwarding, and use only them to forward route requests. Stopping forwarding route requests from the other nodes considerably reduces routing overhead at the expense of possible destination missing. The suggested node caching techniques can be also viewed as a dynamic implementation of a connected dominating set (CDS). We overcome the known drawback of CDS – overuse of dominating (cached) nodes – by a new load-balancing scheme. Our contributions include: (i) a new energy-efficient node caching enhancement of route request broadcast for reactive ad hoc routing protocols; (ii) an extensive simulation study in NS2 of the novel node caching enhancement of AODV (AODV-NC) showing drastic reduction in overhead, significant improvement of the packet delivery ratio and the end-to-end delay and overhead; (iii) an analysis of the forwarding load distribution and energy consumption, and (iv) an extensive simulation study in NS2 of the novel AODV-NC based routing protocol with adaptive workload balancing (AODVNC-WLB) showing considerable improvement in throughput, overhead, delivery ratio and delay over the standard AODV for stressed MANETs.