Emulation of Fading Wireless Link Effects in NEWS Wired Testbed

Currently under development by the Boeing Company, Network Emulator Wireless Simulator (NEWS) is a wired testbed for evaluating the performance of MANET protocols. In part, NEWS extends the Mobile Ad-Hoc Network Emulator (MANE) originally developed by Navy Research Lab (NRL). In this paper, we report the addition of emulation functionality to the NEWS testbed capturing fading wireless link effects. In order to emulate wireless link effects, we develop a finite-state discrete-time Markov chain the parameters of which are extracted from the fading, shadowing, transmission power, modulation type, and antenna configuration characteristics of the underlying link. We extend the implementation of MANE to include our Markov chain. We also investigate the effects of utilizing FEC techniques at the link layer in order to improve the performance of data delivery. Our numerical results show that ignoring the effects of fading can lead to inaccurate modeling of link effects in MANETs. Further, utilizing FEC techniques at the link layer can significantly improve the performance of data delivery over MANETs.