Minimizing routing overhead with Two-Hop Coordinate Awareness in ad hoc networks

We introduce ORTHCA (On-demand Routing with Two Hop Coordinates Awareness) a method for minimizing the dissemination of route requests in mobile ad hoc networks (MANET). The selection of relaying nodes is implemented by first computing the best two-hop relay nodes R₂(u) whose Euclidean Distance to four polar points are the shortest among all two-hop neighbors N₂(u), and then determining one-hop relay nodes R₁(u) connecting with R₂(u). This process is iterated by each member of R₂(u). We prove that all nodes in a connected MANET are covered in the dissemination of route requests using this procedure, and that |R₁(u) + R₂(u)| ≤ 16, which constitutes complexity O(1), regardless of the density of the network. ORTHCA is compared with representative routing protocols, namely AODV, OLSR, LAR, and THP. The simulation results show that ORTHCA reduces the routing load and improves packet delivery ratios, outperforming the other four routing protocols.