Extending Spatial and Temporal Characterization of Indoor Wireless Channels From 350 to 650 GHz

Communication at terahertz carrier frequencies is a promising way to satisfy the ever-growing demands for high-speed wireless networks. The studies of terahertz wireless channels have so far been limited to the atmospheric transmission bands below 350 GHz. Availability of high-power transmitters and high-sensitivity receivers at higher frequencies necessitates extending the wireless channel studies to enable higher data-rate communication systems. With a view to assessing communication system design requirements at higher frequencies, we present the channel measurement results for 650-GHz carrier frequencies in comparison with 350 GHz carrier frequencies in a typical indoor environment. To obtain the spatial and temporal characteristics of the channel, the power angle profile and the power delay profile are measured based on new measurement methods. Multiple spatially resolvable paths are observed at both 350- and 650-GHz carrier frequencies. Signal-to-noise ratio of the received signal through the non-line-of-sight (NLoS) paths is sufficiently high to enable robust communication when the direct line-of-sight (LoS) path is blocked due to a moving object. The measurement results are used to calculate the reduction in the 650-GHz channel capacity in comparison with that of the 350-GHz channel for both LoS and NLoS paths. Channel dispersion characterization over a 10-GHz bandwidth shows that the delay spreads for the resolved LoS and NLoS paths are less than 80 ps for both 350-and 650-GHz bands. Therefore, no complicated equalizer is required to compensate for channel dispersion at both 350 and 650-GHz, which greatly simplifies the terahertz transceiver design.