Real and Simulator Testbeds for Content Dissemination in High-density Large-scale WANET

Yu-Jen Lai1    Youyang Ng1    Takeshi Sakoda1    Yosuke Bando1,2    Arata Miyamoto1
Masahiro Ishiyama1    Ken-ichi Maeda1    Yusuke Doi1

1TOSHIBA Corporation            2MIT Media Lab

A wireless ad hoc network (WANET) is an effective approach to disseminating digital content without the need for infrastructure networks. It is not only useful in the absence of commodity connections such as cellular networks, but also useful for avoiding overloading those connections in crowded scenarios, an example of which is delivering movie clips throughout spectators in a stadium. However, experiments of WANET have been oftentimes conducted using only up to 1,000 nodes in a simulator or dozens of real devices, both typically scattered across a wide area at a density of around 10-4 node/m2. This paper focuses on the problem of disseminating common content to all the devices in the same area via 802.11-based WANET, and presents a pair of testbeds, one based on real devices and the other a simulator, both capable of high-density and large-scale experiments with roughly matched performance. We have found naive implementation of content dissemination protocols alone not to work in high density, and we identify necessary adjustment of wireless parameters to allow for experiments even with an extreme density of 20 nodes/m2. We show that 2.5 MB of data can be delivered to 100 real devices and to 10,000 simulated devices in a few minutes on our testbeds, demonstrating the feasibility of orders of magnitude larger-scale experiments.