ArticlePDF Available

MIMO Channel Capacity Measurement in Open Square Hotspot Access Scenarios at 300 GHz

Authors:

Abstract and Figures

This letter tries to address the fundamental questions on the feasibility of multipath communication and achievable capacity for line-of-sight (LoS), obstructed-line-of-sight (OLoS), and non-line-of-sight (NLoS) scenarios in an outdoor setting for futuristic communication networks. In this context, a relevant measurement campaign at 300 GHz is conducted, and the results are presented in terms of the number of non-trivial propagation paths available for multi-stream data transmission. Encouraged by the obtained results, the average achievable channel capacity for such multi-stream channels is evaluated with and without passive reflecting surfaces (PRS). It is observed a multi-antenna system provides a significant improvement in average capacity compared to a single-antenna system with PRS providing additional enhancement.
Content may be subject to copyright.
... To investigate the environment-dependent trends, both indoor scenarios, such as two different-scale conference rooms [11] and a corridor [5], and an outdoor scenario, an open square hotspot [12], were selected as typical environments, as shown in Fig. 2(a). These results were derived from cluster extraction and power spectrum synthesis, utilizing doubledirectional channel impulse responses obtained through angle scanning measurements. ...
... The distance between the antenna and the scatterer becomes larger, so the number of observable multipath clusters becomes even smaller. In particular, in the open square environment [12], single-bounce Conference room (6m ×8m) ...
Preprint
Full-text available
The THz band (0.1-10 THz) is emerging as a crucial enabler for sixth-generation (6G) mobile communication systems, overcoming the limitations of current technologies and unlocking new opportunities for low-latency and ultra-high-speed communications by utilizing several tens of GHz transmission bandwidths. However, extremely high spreading losses and other interaction losses pose significant challenges to establishing wide-area communication coverage, while human body shadowing further complicates maintaining stable communication links. Although point-to-point (P2P) fixed wireless access in the THz band has been successfully demonstrated, realizing fully mobile and reliable wireless access remains a challenge due to numerous issues to be solved for highly directional communication. To provide insights into the design of THz communication systems, this article addresses the challenges associated with THz short-range mobile access networks. It offers an overview of recent findings on the environment-dependence of multipath cluster channel properties and the impact of human body shadowing, based on measurements at 300 GHz using a double-directional high-resolution channel sounder and a motion capture-integrated channel sounder.
Article
Full-text available
In this paper, a newly developed 300 GHz channel sounder is presented followed by a detailed description of test measurements and the subsequent results obtained to validate its working. An elucidation of the high-resolution double-directional channel measurement in a typical conference room scenario precedes the comparison of the results obtained for the current campaign to that obtained from an earlier campaign at 60 GHz for a similar setup. It is observed that a similar number of clusters for both the bands under investigation for all the transmitter (Tx) and receiver (Rx) positions are obtained from the generated power spectra. Any deviation is theorized to be caused either due to the usage of lower measurement bandwidth in the 60 GHz campaign or due to limited elevation expanse in the 300 GHz measurement. To identify the interacting objects (IOs) causing the clusters, environment-embedded angular power spectra (APS) and ray tracing simulations are used. The large-scale parameters (LSPs) are also evaluated for both campaigns. It is observed that signal propagation in the terahertz (THz) band is dominated more by the line-of-sight (LoS) path compared to the millimeter wave (mm-wave) band (below 100 GHz). The results are also compared with other similar results from the literature.
Article
Full-text available
Design and performance assessment of THz communications systems, which will form an essential part of 6G, require an understanding of the propagation channels the systems will operate in. This paper presents investigations of the channel characteristics in various scenarios at 145 GHz, which is the band currently envisioned for the first round of deployments. In particular, we review several extensive measurement campaigns performed by the University of Southern California in both outdoor and indoor environments. We present the measurement and evaluation methodology and sample results that illustrate the dominant propagation effects in different environments. We then summarize the parameters of the statistical channel models for path loss, delay dispersion, and angular dispersion. Based on these results, we find that even in NLoS (non-line-of-sight) situations, Gbit/s communications can be sustained over a 100 m distance; that (for an antenna gain of 20 dB), there is considerable delay dispersion, requiring tens of equalizer taps, and that angular dispersion is significant in both LoS and NLoS situations. The channel parameters can be thus used as a basis for system design and evaluation under realistic operating conditions.
Article
Full-text available
Antenna, radio frequency (RF) circuit, algorithm, and system researchers on sub-THz RF are interested in knowing characteristics of corresponding radio channels. Among other things, a relevant question is the number of beams supported by the channel. From wideband directional propagation measurements one can estimate how many significant paths are present in a measurement location, but interpreting that to separable beams is not trivial. In this letter, we introduce three methods to approximate the number of beams that a measured power angular delay profile can support. We show also example evaluations and distribution functions of beam numbers, estimated from indoor D-band measurement data.
Article
Due to large reflection and diffraction losses in the THz band, it is arguable to achieve reliable links in the none-line-of-sight (NLoS) cases. Intelligent reflecting surfaces, although are expected to solve the blockage problem and enhance the system connectivity, suffer from fabrication difficulty and operation complexity. In this work, non-intelligent reflecting surfaces (NIRS), which are simply made of costless metal foils and have no signal configuration capability, are adopted to enhance the signal strength and coverage in the THz band. Channel measurements are conducted in typical indoor scenarios at 306-321 GHz and 356-371 GHz bands to validate the effectiveness of the NIRS. Results measured with NIRS in different sizes show that large NIRS performs much better than small NIRS. Furthermore, by invoking the NIRS, the additional reflection loss can be reduced by more than 10 dB and the coverage ratio is increased by up to 39% for a 10 dB signal-to-noise ratio (SNR) threshold.