Session lengths and IP address usage of smartphones in a university campus WiFi network: Characterization and analytical models

Smart mobile handheld devices (MHDs) are being adopted at a fast speed. Compared to wireless non-handheld devices (NHDs), MHDs tend to be more mobile and can be used more opportunistically. In this paper, we study two important network usage characteristics of MHDs, namely session lengths and IP address usage, in a university campus WiFi network. Specifically, we analyze two five-week long DHCP traces collected from the network, characterize session lengths of MHDs, and develop two hyper-exponential models to capture the distribution of session lengths.We further characterize the IP address usage of MHDs, and develop two analytical models to predict the number of concurrent IP addresses that are being used by MHDs at one point of time. Goodness of fit tests indicate that our analytical models of session lengths provide good fit, and evaluation results demonstrate that the predictions from our models for IP address usage are accurate. Our results provide important insights on managing MHDs as they are being adopted rapidly in WiFi networks.