Mapping the Radio World to Find Us

Locating users in an indoor scenario is a challenging task. While there are several systems capable of tackling it, most of them are impractical to deploy in a worldwide scale due to the costs associated with its infrastructure. Therefore, this chapter guides the reader through a popular indoor positioning technique, fingerprinting, which relies on existing infrastructure to provide an estimation of the user’s location. While any kind of signal can be used, such as acoustic and electromagnetic signals, the focus is put on wireless local area network signals, which are ubiquitous in most current buildings. Along the way, the chapter introduces path-loss models, advantages, disadvantages and a thorough description of the inner workings of this technique.