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220 GHz Urban Microcell Channel Measurement and Characterization on a University Campus

Yuanbo Li, Yiqin Wang, Yejian Lyu, Ziming Yu, Chong Han

TL;DR

This work addresses the need for reliable THz channel characterization in urban microcells by conducting a 220 GHz measurement campaign along a campus road with 24 Rx positions. Using a correlation-based time-domain sounder, the authors quantify foliage attenuation, spatial consistency, and a comprehensive set of channel statistics, including path loss, shadow fading, K-factor, delay and angular spreads, and cluster parameters, with comparison to 3GPP expectations. Key findings include a mean foliage loss of $16.74$ dB, LoS K-factor of $17.54$ dB, and an average of about $2.56$ clusters in LoS, illustrating weak multipath and strong sparsity at THz frequencies ($ ext{f}=220$ GHz, $ ext{BW}=1.536$ GHz, $ ext{delay resolution}=0.65$ ns). The results reveal that THz UMi channels exhibit smaller large-scale fading and much larger K-factors than extrapolated from 3GPP models, underscoring the need for THz-specific channel models to inform outdoor THz network design and standardization.

Abstract

Owning abundant bandwidth resources, the Terahertz (THz) band (0.1-10~THz) is envisioned as a key technology to realize ultra-high-speed communications in 6G and beyond wireless networks. To realize reliable THz communications in urban microcell (UMi) environments, propagation analysis and channel characterization are still insufficient. In this paper, channel measurement campaigns are conducted in a UMi scenario at 220~GHz, using a correlation-based time domain channel sounder. 24 positions are measured along a road on the university campus, with distances ranging from 34~m to 410~m. Based on the measurement results, the spatial consistency and interaction of THz waves to the surrounding environments are analyzed. Moreover, the additional loss due to foliage blockage is calculated and an average value of 16.7~dB is observed. Furthermore, a full portrait of channel characteristics, including path loss, shadow fading, K-factor, delay and angular spreads, as well as cluster parameters, is calculated and analyzed. Specifically, an average K-factor value of 17.5 dB is measured in the line-of-sight (LoS) case, which is nearly two times larger than the extrapolated values from the 3GPP standard, revealing weak multipath effects in the THz band. Additionally, 2.5 clusters on average are observed in the LoS case, around one fifth of what is defined in the 3GPP model, which uncovers the strong sparsity in THz UMi. The results and analysis in this work can offer guidance for system design for future THz UMi networks.

220 GHz Urban Microcell Channel Measurement and Characterization on a University Campus

TL;DR

This work addresses the need for reliable THz channel characterization in urban microcells by conducting a 220 GHz measurement campaign along a campus road with 24 Rx positions. Using a correlation-based time-domain sounder, the authors quantify foliage attenuation, spatial consistency, and a comprehensive set of channel statistics, including path loss, shadow fading, K-factor, delay and angular spreads, and cluster parameters, with comparison to 3GPP expectations. Key findings include a mean foliage loss of dB, LoS K-factor of dB, and an average of about clusters in LoS, illustrating weak multipath and strong sparsity at THz frequencies ( GHz, GHz, ns). The results reveal that THz UMi channels exhibit smaller large-scale fading and much larger K-factors than extrapolated from 3GPP models, underscoring the need for THz-specific channel models to inform outdoor THz network design and standardization.

Abstract

Owning abundant bandwidth resources, the Terahertz (THz) band (0.1-10~THz) is envisioned as a key technology to realize ultra-high-speed communications in 6G and beyond wireless networks. To realize reliable THz communications in urban microcell (UMi) environments, propagation analysis and channel characterization are still insufficient. In this paper, channel measurement campaigns are conducted in a UMi scenario at 220~GHz, using a correlation-based time domain channel sounder. 24 positions are measured along a road on the university campus, with distances ranging from 34~m to 410~m. Based on the measurement results, the spatial consistency and interaction of THz waves to the surrounding environments are analyzed. Moreover, the additional loss due to foliage blockage is calculated and an average value of 16.7~dB is observed. Furthermore, a full portrait of channel characteristics, including path loss, shadow fading, K-factor, delay and angular spreads, as well as cluster parameters, is calculated and analyzed. Specifically, an average K-factor value of 17.5 dB is measured in the line-of-sight (LoS) case, which is nearly two times larger than the extrapolated values from the 3GPP standard, revealing weak multipath effects in the THz band. Additionally, 2.5 clusters on average are observed in the LoS case, around one fifth of what is defined in the 3GPP model, which uncovers the strong sparsity in THz UMi. The results and analysis in this work can offer guidance for system design for future THz UMi networks.
Paper Structure (16 sections, 2 equations, 4 figures, 1 table)

This paper contains 16 sections, 2 equations, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. Channel Measurement Campaign
  3. Measurement System
  4. Measurement Campaign
  5. Measurement Setup
  6. Measurement Results and Analysis
  7. Data Post-processing
  8. Propagation Analysis
  9. Foliage Blockage and Attenuation
  10. Statistical Modeling of Channel Characteristics
  11. Path loss and shadow fading
  12. K-factor
  13. Delay and angular Spreads
  14. Cluster parameters
  15. Comparison with 3GPP model
  16. ...and 1 more sections

Figures (4)

  • Figure 1: Correlation-based time-domain channel sounder.
  • Figure 2: The measurement deployment in the UMi scenario. Rx positions are labeled with orange dots.
  • Figure 3: The spatial consistency analysis along the Nanyangdong Road. PDPs measured in different Rx locations are shown in (a), while the objects affecting the THz propagation are shown in (b).
  • Figure 4: The propagation loss of the LoS/OLoS path and additional loss due to foliage.