Model-Based Analysis of IEEE 802.11 Link Performance Using Wireless Packet Capture

In this work, we propose a novel mechanism to assess and interpret Wi-Fi link performance by analyzing packet capture from a Wi-Fi radio in monitor mode. Using a model of DCF/EDCA mechanism, we highlight the impact of finer performance measures, including channel access delay, transmission opportunities, collision and retransmission rates, on the performance of a saturated Wi-Fi link. By analyzing the wireless packet capture, we investigate the evolution of the Wi-Fi radio through the transmission opportunities, idle/backoff durations and channel busy states, to measure the above mentioned finer link metrics. The pcap analysis permits us to quantify non Wi-Fi energy in the channel, detect instances of unfair channel access and identify hidden/parallel transmissions. These findings provide valuable insights into explaining the measured link metrics and throughput performance. We illustrate the utility and effectiveness of our proposal by reviewing Wi-Fi link performance in a variety of test network scenarios.