Modeling environmental mobility and its effect on network protocol stack

In this paper we address the effects of environmental mobility, that is, the ambient motion of entities like people and vehicles in the vicinity of wireless communication, on the channel characteristics and wireless network performance. We present a three step process of measurements, modeling and network simulations to quantify the significance of environmental mobility. Our field experiments show that presence of people not only cause deep fades but also distorts the fading distribution. We model the shadowing loss by three knife-edge diffraction model and propose a two-state Markov process channel fading behavior. The models are validated against measurement data and implemented in a network simulator. The models are scalable and incur execution overhead less than 15%. We also show the impact of environment mobility on protocol performance by means of two simulation case studies. We show that MAC layer data rate adaptation behavior is sensitive to environmental mobility and can result in 40% packets being delivered at lower rates. Second study on ad-hoc network performance show the throughput is decreased by 20%. We have identified that with environmental mobility the links are more sensitive to interference and the routes are less stable