An FPGA Implementation of Improved AODV Routing Protocol for Route Repair Scheme

The ad hoc on demand distance vector (AODV) routing protocol is a dynamic, self starting protocol used in mobile ad hoc networks (MANET)s which is basically a collection of mobile nodes that can communicate with each other. This routing protocol functions without any need for fixed infrastructure or base station. It has the following advantages like low processing rate, memory overhead, and low network utilization. In spite of these advantages, AODV suffers from the limitation of low bandwidth i.e., used for long period when bandwidth is low. The improved AODV routing protocol with route repair scheme overcomes the disadvantages of its predecessor. In the earlier AODV routing protocol, wherever a link breaks an error message is sent to the source stating that a link failure has taken place and further communication is stopped temporarily. Where as in the improved version, nodes in the active path between source and destination act as a virtual source when link breakage occurs and there by the search process is continued till the link is formed to reach the original destination is reached. Comparison between original routing protocol and the improved algorithm is carried out by simulating them in MODELSim, simulation software and the VHDL coding is implemented in FPGA Virtex-IV kit.