Designing radio interferometric positioning systems for indoor localizations in millimeter wave bands

Recently, millimeter wave (MMW) systems that operate at 60 GHz are proposed for the short-range communications to reduce the interference. Taking advantage of the spectrum characteristics of MMW bands, the indoor localization system using the radio interferometric positioning system (RIPS) employing space-time coding is proposed in this paper. The RIPS is a promising localization scheme for its low complexity and high accuracy, and the space-time RIPS (STRIPS) is the enhancement of the RIPS to work in MMW bands under the flat-fading channel. Two anchor nodes simultaneously transmit at two time slots with different frequencies, and the signal is sampled at the low-sampling frequency at the target node. The STRIPS achieve the range-difference (RD) estimate without approximation and is immune to channel fading effects. To accommodate the frequency offsets, the ESPRIT-based algorithm is adopted. Monte-Carlo simulation results are presented to confirm the performance of the STRIPS.