Mobility Models for Next Generation Wireless Networks

Chapter 9

Real-World WLAN Mobility

Given its importance within the realm of short-range wireless technologies, WLAN performance has been carefully investigated in the literature. In particular, since it is relatively easy to trace AP activity in terms of number of registered users, traffic load, etc., collection of real-world data traces and their analysis have become a common methodology in WLAN performance evaluation.

In this chapter, after briefly describing the main features of the WLAN traces available in the literature (most typically through the CRAWDAD website), and the typical methodologies followed by researchers to collect, post-process, and analyze these traces, we will present the main features of a WLAN that concern the mobility of users. These features have been used in the literature to guide the design of trace-based mobility models, whose purpose is to faithfully mimic user mobility behavior observed in WLAN traces.

9.1 Real-World WLAN Traces

As commented above, tracing user behavior in a WLAN environment is a relatively simple task: since APs typically have a direct connection to a wired network (e.g., the campus or corporate network), and users need to be registered with an AP in order to use WLAN services, instructing APs to periodically report information such as number of registered users, their IDs, traffic load, etc., is relatively simple. As we will see, much more cumbersome is the task of post-processing and analyzing the possibly massive amount of logging ...