Why Wi-Fi Fails
A diagnostic system determines where and why buildingwide
systems falter

SOURCE: “Automating Cross-Layer Diagnosis of Enterprise Wireless ­Networks”
Yu-Chung Cheng et al.
Proceedings of the ACM Sigcomm ­Conference, Kyoto, Japan, August 2007

RESULTS: Researchers at the University of California, San Diego, have developed a system that tracks wireless traffic in a building and determines precisely what causes signals to dip, traffic to slow, and laptops to get kicked off the network.

WHY IT MATTERS: Wi-Fi tends to be unreliable. A number of factors can interfere with a signal, from hardware malfunctions and software bugs to interference from microwave ovens and cordless phones. What’s more, the degree of influence these factors have can change quickly, making Wi‑Fi failures difficult to anticipate and diagnose. An efficient way to pinpoint problems would make them much easier to correct.

METHODS: The researchers installed 192 radios to monitor traffic throughout the university’s computer science building. To infer wireless activity that wasn’t measured directly, they developed novel algorithms that extracted clues from the measured data. Using both the measured and the inferred data, they were able to determine how much each interfering factor contributed to Wi-Fi problems. The researchers think the technology could be implemented quickly. They say manufacturers could easily equip routers with traffic-monitoring hardware, along with software that analyzes network activity.

NEXT STEPS: The researchers will explore the technical challenges of deploying the system and maintaining constant network analysis.