CAD-HOC: a CAD-Like tool for generating mobility benchmarks in ad-hoc networks

The paper addresses the problem of using unrealistic mobility scenarios for simulation of ad-hoc routing protocols. We present CAD-HOC, a cousin tool to Network Simulator (ns), which allows ad-hoc networking experimentation to be performed under visually realistic scenarios such as an airport or a bus terminal, buildings, highways and other facilities. CAD-HOC focuses on capturing the visual scenario and transforming it into mobility and connection benchmarks, which are subsequently fed to ns to drive simulation experiments. Generation of mobility and connection benchmarks is facilitated by allowing the users to choose from Brownian, Column, Pursue, and Nomadic models, or to specify user-defined movements. The tool also provides online analyses on ad-hoc mobility, ad-hoc connectivity and message complexity, which give an estimate of the overall ns simulation complexity, as the mobility scenario is built. Comparative simulation based on CAD-HOC generated scenarios raise several questions about the reliability of ns simulation results of ad-hoc routing protocols based on random, nonrealistic scenarios.