Statistical modeling of propagation channels for Terahertz band

Abstract

Abstract-Digital revolution and recent advances in telecommunications technology enable to design communication systems which operate within the regions close to the theoretical capacity limits. Ever-increasing demand for wireless communications and emerging numerous high-capacity services and applications mandate providers to employ more bandwidth-oriented solutions to meet the requirements. Trend and predictions point out that marketplace targets data rates around 10Gbps or even more within the upcoming decade. It is clear that such rates could only be achieved by employing more bandwidth with the state-of-theart technology. Considering the fact that bands in the range of 275GHz-3000GHz, which are known as Terahertz (THz) bands, are not allocated yet for specific active services around the globe, there is an enormous potential to achieve the desired data rates. Although THz bands look promising to achieve data rates on the order of several tens of Gbps, realization of fully operational THz communications systems obliges to carry out a multidisciplinary effort including statistical propagation and channel characterizations, adaptive transceiver designs, reconfigurable platforms, advanced signal processing algorithms and techniques along with upper layer protocols equipped with various security and privacy levels. Therefore, in this study, several important statistical parameters for line-of-sight (LOS) channels are measured. High resolution frequency domain measurements are carried out at single-sweep within a span of 60GHz. Impact of antenna misalignment under LOS conditions is also investigated. By validating exponential decay of the received power in both time and frequency domain, path loss exponent is examined for different frequencies along with the frequency-dependent path loss phenomenon. Furthermore, impact of humidity is also tested under LOS scenario. Measurement results are presented along with relevant discussions and future directions are provided as well.

Terahertz communication: The opportunities of wireless technology beyond 5G

“…Designing closeproximity communication systems at THz frequencies will actually be permitted through the proposed channel model. Another recent study on the statistical channel characterization of a THz scenario has been presented in [27]. The study tackles the frequency range between 240 and 300 GHz; yet, it is one of the first to provide single-sweep THz measurement results.…”

Error Analysis of Mixed THz-RF Wireless Systems

“…The con of the above mentioned contributions is that they overestimated the THz system performance, since they neglect the impact of fading, which can be generated due to scattering on aerosols [7]. On the contrary, in [8] and [9], the authors modeled fading as stochastic processes. In particular, in [8], they experimentally proved that the envelope of the fading coefficient follows Nakagami-m distribution under both non-line-of-sight and line-of-sight conditions.…”

Analytical Performance Evaluation of THz Wireless Fiber Extenders

“…Although all the above contributions revealed the particularities of the THz medium, they neglected the impact of fading, which can be generated due to scattering on aerosols in the atmosphere [20]. On the contrary, in [21]- [24], the authors presented suitable stochastic models that are able to accommodate the multipath fading effect in the THz band. In particular, in [21], the authors introduced a multi-path THz channel model, where the attenuation factor was modeled as a Rayleigh or Nakagami-m distributions under the non-line-of-sight condition and as a Rician or Nakagami-m distribution under the line-of-sight assumption.…”

“…On the contrary, in [21]- [24], the authors presented suitable stochastic models that are able to accommodate the multipath fading effect in the THz band. In particular, in [21], the authors introduced a multi-path THz channel model, where the attenuation factor was modeled as a Rayleigh or Nakagami-m distributions under the non-line-of-sight condition and as a Rician or Nakagami-m distribution under the line-of-sight assumption. Moreover, in [22] and [23], the authors assumed Rician fading to accommodate the stochastic characteristics of the THz communication channel.…”

“…The impact of TX-RX beams misalignment in the THz link was discussed in [21], [23] and [25]. In more detail, in [21] and [25], the authors assumed deterministic models to incorporate the impact of antennas' misalignment, while, in [23], it was considered to be a part of the shadowing effect. The disadvantage of these models is that they are unable to accommodate the stochastic characteristics of phenomena such as thermal expansion, dynamic wind loads and weak earthquakes, which result in the sway of high-rise buildings and cause vibrations of the transceivers antennas; in other words, the effect of misalignment between the TX and RX [26].…”