Indoor Localization By Detecting 80 Key Bits With Downlink Interleave Division Multiple Access

In this paper, a wireless cellular network based indoor localization approach is presented. During the training stage, the mobile device initializes a positioning request. The surrounding Base Stations (BSs), which are typically equipped with massive antenna array elements, can measure the Angle of Arrival (AoA) of the positioning request signal. Being unsimilar to the conventional AoA localization approaches, the BSs will not communicate with each other and localize the mobile device cooperatively. Instead, each BS simply encodes its own longitude, latitude and AoA information within a 80-bit small packet. Further, before delivering the data to the mobile device, downlink Interleave Division Multiple Access (IDMA) is exploited. Hence, during the measurement stage, the mobile device receives the superposition of the data packet from multiple BSs. Downlink IDMA manages to detect the superimposed data robustly even under the asynchronous environment. Numerical results exhibit that 90% of the realizations can yield a positioning error smaller than one meter, under very low Signal-to-Noise Ratio (SNR).