# Why It Takes So Long to Connect to a WiFi Access Point

## TL;DR

This study analyzes large-scale WiFi connection data to understand setup delays and proposes a machine learning strategy that drastically reduces connection failures and setup times, improving user experience.

## Contribution

It is the first large-scale measurement study on WiFi connection setup times and factors affecting them, leading to a machine learning-based AP selection method.

## Key findings

- Connection setup failure rate reduced from 33% to 3.6%.
- Connection setup time reduced by more than 10 times for 80% of cases.
- Identified key factors influencing WiFi connection delays.

## Abstract

Today's WiFi networks deliver a large fraction of traffic. However, the performance and quality of WiFi networks are still far from satisfactory. Among many popular quality metrics (throughput, latency), the probability of successfully connecting to WiFi APs and the time cost of the WiFi connection set-up process are the two of the most critical metrics that affect WiFi users' experience. To understand the WiFi connection set-up process in real-world settings, we carry out measurement studies on $5$ million mobile users from $4$ representative cities associating with $7$ million APs in $0.4$ billion WiFi sessions, collected from a mobile "WiFi Manager" App that tops the Android/iOS App market. To the best of our knowledge, we are the first to do such large scale study on: how large the WiFi connection set-up time cost is, what factors affect the WiFi connection set-up process, and what can be done to reduce the WiFi connection set-up time cost. Based on the measurement analysis, we develop a machine learning based AP selection strategy that can significantly improve WiFi connection set-up performance, against the conventional strategy purely based on signal strength, by reducing the connection set-up failures from $33\%$ to $3.6\%$ and reducing $80\%$ time costs of the connection set-up processes by more than $10$ times.