Transmission range and frame error process in rural area Wi-Fi networks

Few researchers have performed measurements of a Wi-Fi channel at the frame level in order to understand performance issues by relating frame errors and signal strength. This paper presents results relative to ad hoc measurements in a rural environment. We show that a simple double regression propagation model like the one used in the ns-2 simulator can miss important transmission impairments that are apparent even at short transmitter-receiver distances. We propose a two- ray propagation model which improves on those commonly used for simulation purposes. Frames were transmitted and received by using two cheap laptops with standard Linux drivers. Measurements also show that packet loss at the frame level is a Bernoullian process for time spans of few seconds, and that longer time spans exhibit a more complex behaviour, meaning that the 2-state Markov-modulated process often used in the literature is not a good match for rural areas.