Distance and Tag Aware Localization in Indoor Terahertz Systems

The accuracy of radio frequency identification (RFID) based time-of-flight ranging is considerably affected by the wireless channel within an indoor radio environment, where the bandwidth is considered the major limited factor for localization accuracy. Terahertz (THz) band offers bandwidth orders of magnitude greater than the lower-frequency communications; however, this band has different prorogation mechanisms influencing a wireless transmission compared to the lower frequency bands. The bandwidth of transmission at THz band is highly distance-dependent. Furthermore, since the wireless channel of RFID systems is a two-way pinhole channel, the design of the tag plays a key-role in capturing the usable bandwidth in THz bands. This paper studies RFID based localization at THz band in indoor environments. We analyze the impact of distance and tag design on the RFID link budget. We also characterize the tag and distance dependent spectral windows that are feasible for RFID based localization. The localization requirements for RFID based localization are also presented in order to achieve high accuracy localization.