Dartmouth’s Computer Science Department has released a technical report comparing actual wireless network performance with what both models and most people think wireless performance actually is.

Quoting from the abstract:

Although it is tempting to assume that all radios have circular range, have perfect coverage in that range, and travel on a two-dimensional plane, most researchers are increasingly aware of the need to represent more realistic features, including hills, obstacles, link asymmetries, and unpredictable fading. Although many have noted the complexity of real radio propagation, and some have quantified the effect of overly simple assumptions on the simulation of ad~hoc network protocols, we provide a comprehensive review of six assumptions that are still part of many ad~hoc network simulation studies. In particular, we use an extensive set of measurements from a large outdoor routing experiment to demonstrate the weakness of these assumptions, and show how these assumptions cause simulation results to differ significantly from experimental results.