Wataru Yamada’s research while affiliated with Nippon Telegraph and Telephone and other places

... This setup fails to capture the omnidirectional multipath characteristics, where significant multipath rays can arrive from 360° in the azimuth plane, as demonstrated in this study. An exception is the work in [24], which conducted measurements in a real office desk environment within the 110 [31]. However, these studies typically focused on longer-range communications, such as cellular or WLAN-type communications, where the propagation characteristics differ significantly from those in personal office desk environments. ...

Reference:

105 GHz Multipath Propagation Measurement and Comparison with 60 GHz in Office Desk Environment for Ultra-High Speed Sub-THz WPAN Systems

... The authors of [17] developed a sub-THz massive multipleinput multiple-output (MIMO) channel sounder using 896 antenna elements, offering a high time-spatial channel resolution. The developed channel sounder could determine how many pathways arrived with a lower received power in real time. ...

Reference:

Transceiver Design of a Secure Multiuser FDSS-based DFT-Spread OFDM System for RIS-and UAV-assisted THz Communications

... The authors of [7] utilized visual data obtained from multi-view sensing cameras to predict path loss. The authors of [8] utilized side-view images between the transmitter and receiver, along with frequency information, to predict path loss. The work in [9] employed 2D satellite images of the target area as input to a deep neural network to predict path loss distributions at various UAV altitudes. ...

Reference:

Multi-Modal Environmental Sensing Based Path Loss Prediction for V2I Communications

... For DOA measurement, methods using array antennas with super-resolution algorithms [4,5] and methods using physically rotating large aperture antennas [6,7] are employed. For frequencies beyond 100 GHz, the first method is not easy to prepare array antennas. ...

Reference:

Improvement of angular dependence of angular profile in DOA measurement method using rotating reflector antenna

... In next-generation mobile communications, the proactive use of millimeter-wave (mm-wave) and terahertz-wave (THz-wave) frequencies, which can secure a wide frequency bandwidth, is anticipated to achieve further high-speed and large-capacity communications. Various studies have reported on the characteristics of path-loss, delay, and direction-of-arrival (DOA) for these frequencies in different scenarios [1][2][3]. ...

Reference:

Improvement of angular dependence of angular profile in DOA measurement method using rotating reflector antenna

... In [74] the imaging method, a variant of ray tracing, is approached with a quantum annealer. Given a number of VOLUME 11, 2023 interactions N and a set of M interaction objects, the problem to be solved is to find the dominant propagation path, i.e., the path that experiences exactly N reflections or diffractions and has minimal propagation loss (PL). ...

Reference:

Quantum Algorithms in Electromagnetic Propagation Modelling for Telecommunications

... Several applications of DNN for the next generation of wireless communication systems (e.g., 6G) have recently emerged [3]. Models utilizing this technique have been proposed for path loss estimation, which is essential for the cell and system design of wireless communications [4,5,6,7]. These models use the convolutional neural network (CNN) as the DNN [5,7], which enables feature quantities (e.g., building profile) to be automatically and internally extracted from input images and utilized for estimation. ...

Reference:

Deep-learning path loss prediction model using side-view images

... Despite promising features, major challenges in the effective usage of higher frequency bands include high free space path loss (FSPL), atmospheric attenuation in gasses and rainfall, and non-line of sight (NLOS) propagation issues, that lead to the degradation of signal-to-noise ratio (SNR) and data rates [11][12][13][14][15]. To solve these issues, high-gain and highly-directive antennas have been commonly used; however, as a result, the beam coverage has become quite narrow, limiting the practicality of such systems. ...

Reference:

Multilayer-laminated optically transparent 300-GHz-band transmissive beamforming metasurface for wireless communication

... 10 to 100 times of the current 5G peak rate [4]. The other characteristics encompass remarkable penetrability [5], the capacity to traverse non-metallic materials without inflicting any damage, and the low energy levels that minimize harm to living organisms, thereby facilitating non-destructive testing. ...

Reference:

Generalized Filter Bank Orthogonal Frequency Division Multiplexing: Low-Complexity Waveform for Ultra-Wide Bandwidth and Flexible Services

... Against the previous methods, Sotiroudis et al. [19] developed a long short-term memory neural network for the prediction of PL with the frequency of 2-26 GHz. Other relevant works adopted DL or ML to predict PL over a channel [20]- [22]. Some of the methods are support vector machine (SVM) [23], random forest [24], and K-nearest neighbors (KNN) [25]. ...

Reference:

PATH LOSS PREDICTION IN THE TROPICS USING BROADCAST SIGNAL: A DEEP LEARNING FRAMEWORK