Experimental Study of Hidden-node Problem in IEEE 802 . 11 Wireless Networks *

The Hidden-node problem is a well-known phenomenon in IEEE 802.11 wireless networks. Most previous studies of the hiddennode problem were conducted by simulations, not experiments. In this paper, we set up real-network experiments to investigate the impact of hidden nodes in both infrastructure and multi-hop adhoc networks. Our experiments suggest transmission and carriersensing channel models different from those in the default settings of the NS2 simulator. We also study the RTS/CTS mode as a solution to the hidden-node problem. We show that using either 2Mbps or 11Mbps to transmit RTS/CTS not only can not solve the problem, but also further degrades the throughput by introducing additional overhead. In addition, our experiments confirm the existence of “re-routing instability” and “optimal offered load” in multi-hop ad-hoc networks which have only been previously “seen” in simulations.