Integrating Localization and Communication for Multiple Backscatter Tags With Commodity WiFi

In recent years, backscatter technologies are booming towards the vision of embedding cheap connectivity into billions of everyday objects in the era of Internet of Things (IoT). Localizing backscatter tags using existing ubiquitous WiFi infrastructures is crucial for a wide range of IoT applications, such as inventory management, asset monitoring, as well as personal security. However, current backscatter localization system localizes only a single backscatter tag by using multiple access points (APs), which are not available in typical indoor environments, such as homes and small businesses. This paper presents TagsLoc, the first system that only uses a single WiFi AP to localize multiple backscatter tags and the transmitter simultaneously. TagsLoc separates signals corresponding to each backscatter tag by leveraging both spatial and frequency domain diversity. Then, it localizes all the backscatter tags by fusing multi-dimensional information based on the triangle theory. The numerical results show that TagsLoc can localize multiple backscatter tags and the transmitter simultaneously with decimeter-level accuracy.