Prongle: Lightweight communication over unassociated wi-fi

Abstract

Wi-Fi capability has been a standard feature on mobile devices for over a decade. Despite Wi-Fi being practically ubiquitous, its usage has been limited to locations where the user is authorized to use a provided WLAN, e.g. home, office, or "free Wi-Fi" offered by some entity. Authenticating and associating to a previously unknown WLAN is a tedious process to go through only for the sake of e.g. receiving a push message, contributing in a public event with a smartphone, or finding out about surrounding traffic or services. There are several use cases where a lighter version of Wi-Fi could satisfy the communication need. In this paper we present the Prongle system - a lightweight, opportunistic, association-free communication system for smart devices over conventional Wi-Fi hardware. Our system consists of a small carry-on companion device and an Android smartphone which the prongle is paired to over Bluetooth. The prongle device is effectively a message forwarding proxy dongle, hence the name Prongle. We explain the inner workings of our prongle device, present the user-interface application, and finally evaluate the system in both device-to-device range and round-trip time.