I Am the Antenna: Accurate Outdoor AP Location using Smartphones Zengbin Zhang†, Xia Zhou†, Weile Zhang†§, Yuanyang Zhang†, Gang Wang†, Ben Y. Zhao† and Haitao Zheng† †Department of Computer Science, UC Santa Barbara, CA 93106, USA §School of Electronic and Information Engineering, Xian Jiaotong University, P. R. China {zengbin, xiazhou, yuanyang, gangw, ravenben, htzheng}@cs.ucsb.edu,
[email protected] ABSTRACT 1. INTRODUCTION Today’s WiFi access points (APs) are ubiquitous, and pro- WiFi networks today are ubiquitous in our daily lives. vide critical connectivity for a wide range of mobile network- WiFi access points (APs) extend the reach of wired networks ing devices. Many management tasks, e.g. optimizing AP in indoor environments such as homes and offices, and en- placement and detecting rogue APs, require a user to effi- able mobile connectivity in outdoor environments such as ciently determine the location of wireless APs. Unlike prior sports stadiums, parks, schools and shopping centers [1, 2]. localization techniques that require either specialized equip- Even cellular service providers are relying on outdoor WiFi ment or extensive outdoor measurements, we propose a way APs to offload their 3G traffic [2, 3]. As Internet users be- to locate APs in real-time using commodity smartphones. come reliant on these APs to connect their smartphones, Our insight is that by rotating a wireless receiver (smart- tablets and laptops, the availability and performance of to- phone) around a signal-blocking obstacle (the user’s body), morrow’s networks will depend on well tuned and managed we can effectively emulate the sensitivity and functionality access points.