Communication Channel Model Research Articles

Low-complexity characterized-long-short-term-memory-aided channel modeling for optical fiber communications

In this work, a low-complexity data-driven characterized-long-short-term-memory (C-LSTM)-aided channel modeling technique is proposed for optical single-mode fiber (SMF) communications. To fully utilize the sequence correlation learning ability of traditional long short-term memory (LSTM) networks and solve the gradient explosion problem, the feature information is introduced into the traditional LSTM input layer to better characterize the intersymbol interference caused by dispersion in SMF modeling. The simulation results show that the proposed C-LSTM can effectively alleviate the gradient explosion problem with a stable and ultimately lower mean square error (MSE) than traditional LSTM. Compared with the split-step Fourier method (SSFM) and the conditional generative adversarial network (CGAN), the proposed C-LSTM has superior computational complexity. Moreover, due to the sequence correlation learning ability inherent to C-LSTM, coupled with the flexibility of feature information selection, the proposed C-LSTM-aided modeling technique has a higher modeling accuracy than traditional LSTM. Moreover, the C-LSTM-aided modeling technique can be effectively extended to other channel modeling applications with strong sequence correlations.

A Novel 6G ISAC Channel Model Combining Forward and Backward Scattering

The integrated sensing and communication (ISAC) refers to the integration of radio sensing and wireless communications to realize the multiplexing of space, time, and frequency resources. In the sixth generation (6G) wireless networks, ISAC is considered as one of the most promising technologies. In this paper, a novel ISAC channel model combining forward and backward scattering is proposed. In addition to the non-stationarity caused by motions, the correlations between sensing and communication channels are investigated. The channel characteristics of sensing such as forward scattering and backward scattering are introduced into the communication channel model. Utilizing the correlations between sensing and communication channels, the communication channel model is divided into line-of-sight (LOS), forward scattering, and backward scattering components. These three components are summed according to probability weighting to obtain a more accurate channel model for sensing assisted communication systems. Moreover, important statistical properties of the proposed ISAC channel model are derived and simulated. The analytical and simulation results match well, demonstrating the correctness of derivations and simulations. Some derived/simulated statistical properties are verified by corresponding measurement data, which indicates the utility of the proposed ISAC channel model.

MODEL FOR CALCULATION OF THE ENERGY POTENTIAL OF A SATELLITE RADIO LINK WITH ACCOUNT OF THE TRAJECTORY

A model of satellite communication channel taking into account the trajectory, specifically developed for low Earth orbit satellite constellations, is presented. Low and high orbits have different advantages and limitations. To efficiently utilize resources in low Earth orbit satellites, it is necessary to forecast changes in the energy potential and adapt the parameters of satellite modems. For this purpose, there are such programs as Computer-Aided Design (CAD) "Albatross" for evaluating the dynamics of resource changes. However, a realtime model has been developed for the operational management of modems, allowing the construction of temporal diagrams depicting changes in the energy potential of communication channels. The development of such models can be performed in the LabVIEW environment, a software developed by National Instruments for creating virtual instruments (VIs). The development process includes considering the motion of the satellite in a user-defined orbit, taking into account various parameters. SubVIs are used to simplify program creation, improve code readability and enable element reuse. To construct one orbit the number of iterations in the loop is calculated, which is the rounded value of the orbital rotation period divided by the time difference between the calculated sub-satellite points. The smaller the value of the time difference is, the more accurate the trajectory will be. Constructing a trajectory with a larger number of revolutions requires more time. For performing the energy calculation, the antenna pattern (AP) is calculated, and a satellite trajectory is constructed with the cross-section of the antenna pattern on Earth. The developed model allows evaluation of the satellite trajectory for a given number of revolutions around the Earth and conducting energy potential calculations for a specified location of the Earth station. The results can be used for building algorithms for adaptive control of parameters in satellite radio links.

Characterization and modeling of high-speed underwater acoustic communication channels

High-speed mobile underwater acoustic communication (HSM-UAC) is a relatively unexplored terrain, but its importance is expected to increase with the widespread application of flexible underwater mobile platforms such as AUVs and UUVs. Knowledge of HSM-UAC channels is a prerequisite to achieving reliable communication. This work conducted two HSM-UAC channel measurement experiments with a maximum speed of 20knots. The analysis of channel time-varying characteristics demonstrates the shortcomings of traditional consistent Doppler frequency offset channel model. The experimental findings reveal the presence of two non-stationary modes in the HSM-UAC channel. For short moving distances, the changes in channel geometry result in each path experiencing a different Doppler scale, thus observing the multiscale-multilag (MSML) channels. For long moving distances, the alteration in sound ray propagation tracks entirely reshapes the channel impulse response (CIR) structure, leading to a rapid decline in channel time correlation. In further analysis, the correlation coefficient of the power delay profile (PDP) is used to measure channel stationarity. Subsequently, the stationary time and corresponding stationary distance are calculated as characterization parameters for the time-varying channel model. The quantitative evaluation results are helpful for the communication signal design and determining the update frequency of channel state information.

Cluster control technology of transmission line intelligent inspection drones based on 5G communication

Abstract This paper firstly analyzes the network topology model of the UAV cluster network and wireless 5G communication channel model by modeling and briefly analyzes the idea of topology movement control for flying self-organized networks. Then, a cluster-based structure and reinforcement learning clustered routing protocol is proposed for the problem of easy breakage of routing forwarding paths caused by smart inspection of transmission lines based on UAV clusters for 5G communication. Finally, a cluster structure-based precedence routing protocol is designed, an adaptive routing protocol based on location and link quality Q-learning is used between clusters, and fast and reliable routing is achieved by combining the routing table maintained by itself. The simulation results show that ARP-L-Q (average end-to-end delay 4.22, average packet loss rate 88.09%, average packet rate 2.37, average control overhead 2.52) protocol performs better than GPSR and GACB protocols, and the experiment verifies that ARP-L-Q protocol can better achieve the high dynamic reconfiguration, high stability and reliability, and low communication delay of UAV cluster-based 5G communication network. Characteristics and requirements. This study has application prospects in both civil emergency and military mobile communication and has certain military significance, theoretical value and application value for thus promoting UAV innovation.

Channel modeling for V2V communication: Enhancing road safety and intelligent transportatio

The advancement of the Internet of Things (IoT) and Vehicle-to-Vehicle (V2V) communication networks has led to increased research efforts toward developing efficient and innovative V2V communication systems. These systems are designed to achieve the goal of improving road safety and enabling intelligent transportation. A critical aspect of this effort is channel modeling. In this context, this paper summarizes the characteristics of V2V communication channels. It categorizes them into three main types: Deterministic models, Non-geometry stochastic models (NGSMs), and Geometry-based stochastic models (GBSMs). It then reviews recent literature on these three types of channel modeling methods and discusses future development directions and challenges for V2V channel modeling. The study highlights the importance of accurate channel modeling for successful V2V communication systems and emphasizes the need to consider the unique features of V2V channels. It also identifies the limitations of existing channel models and suggests areas of research that can lead to more reliable and efficient V2V communication systems.

Algorithmic Solutions in the Problem of Evaluating the Quality of Communication with an Unmanned Aerial Vehicle

Algorithmic solutions have been developed to assess the quality of communication with an unmanned aerial vehicle. The quality of communication is determined by the probability of a symbol error at the input of an error-correcting encoder, the a priori calculation of which is performed in the approximation of Rice’s communication channel model. The main attention in the solution is given to the determination of attenuation due to the combined influence of the terrain and tropospheric refraction on the energy parameters of the line ground communication point–unmanned aerial vehicle. The attenuation was calculated by jointly solving a pair of parabolic equations formed from the two-dimensional Helmholtz equation in narrow- and wide-angle approximations by the pseudospectral method of separating the steps of a pair of parabolic equations. In the features of the main stages of the algorithmic implementation of the developed solution are highlighted, and its performance is tested on specific test examples.

МОДЕЛИРОВАНИЕ ПРОЦЕССОВ ВОЗДЕЙСТВИЯ ИМПУЛЬСНЫХ ПОМЕХ ПЕРЕМЕННОЙ ДЛИТЕЛЬНОСТИ НА СИСТЕМУ СВЯЗИ СТАНДАРТА IEEE 802.15.4-2020

The noise immunity of radio communication systems based on IEEE 802.15.4–2020 and IEEE 802.15.4z–2020 standards under interference effect of variable-duration impulse noise is investigated. The simulation model of a radio communication channel for estimation of the bit error rate for noise with different parameters is developed using the MATLAB. The estimates of the noise immunity for different standard modes taking into account the structure of transmitted data are obtained. The comparison between the characteristics of standard modes is performed. A developed model can be modified for estimation of the noise immunity under interference effect of others types of noise. The obtained results of noise immunity estimation can be used for development of perspective ultra-wideband radio communication systems and increasing the efficiency of existing radio communication systems.

КАНАЛЫ ПЕРЕДАЧИ НАУЧНОЙ ИНФОРМАЦИИ КОСМИЧЕСКОГО АППАРАТА «ЧИБИС–АИ»

In the paper an option of scientific information communication link, based on SDR technology, for “Chibis–AI” spacecraft is considered. The program package GNU Radio 3.10 has been used. To satisfy technical requirements for data rate new additional program blocks for GNU Radio 3.10 have developed. Engineering model of scientific data communication channels have been produced. Correspondence of the measured communication channels specifications for technical requirements has been show.

Study of Power and Trajectory Optimization in UAV Systems Regarding THz Band Communications with Different Fading Channels

Researchers are interested in unmanned aerial vehicles (UAVs) because they have many uses in current 5G and future 6G networks and are safer than human-operated vehicles. Terahertz (THz)-band communications are a possible option in 6G for fast communication. THz wireless communication between UAVs is taken into consideration in this work. Different fading channels, which are significant influencing factors in THz communication channel modeling, are used to analyze the performance of UAV communications in THz networks. Consideration must be made to the structure, wireless channel parameters, and transmission characteristics when evaluating the performance of wireless technology. Nakagami-m, Rician, Weibull, and Rayleigh fading channels are all taken into consideration, along with log-normal fading. Moreover, an optimization algorithm for the THz channel is presented, which is meant to minimize transmission power by optimizing the trajectory of uplink and downlink transmissions between the UAV and users. The equations of the UAV locations and the transmission power optimization of each user are derived. Analytical formulations regarding capacity, outage probability, and bit error rate (BER) are generated when performance-influencing factors are taken into account. The analytical analysis is supported by the numerical results that are provided.

Помехоустойчивость когерентного приема сигналов с многопозиционной фазовой манипуляцией и синусоидальной огибающей в гидроакустическом канале связи

Goals: The main purpose of this work is to develop a methodology for determining the parameters of signals with multi-position phase manipulation (M-PSK), in which the signals become relatively invariant to frequency distortions in the marine environment. The frequency distortion of the signals is caused by the uneven frequency response of the attenuation of the marine environment. The main part of this technique is to assess the effect of frequency distortion of signals on the noise immunity of reception. To do this, the error probabilities of the M-PSK signal receiver are determined, which is optimal in the absence of distortion. Methods: The provisions of applied hydroacoustics, the theory of random processes and the theory of transmission of discrete messages are used. The main content: The paper considered a model of a single-beam hydroacoustic communication channel, characteristic of the deep sea, when the receiver or transmitter is located in the depths of the sea. The transmission coefficient of the channel is used as a transmission coefficient with a Gaussian amplitude -frequency response and a linear phase-frequency response. The additive boundary of the error probability for coherent reception of M-PSK signals with a sinusoidal envelope is determined. As a receiver, a coherent receiver is considered, optimal by the criterion of maximum likelihood under the action of white Gaussian noise and the absence of distortion in the marine environment. A logarithmic measure of increasing the probability of error is introduced, which characterizes the deterioration of noise immunity due to frequency distortions in the channel. For some typical cases, the values of signal parameters that are relatively invariant to frequency distortions in the marine environment are determined. Results: Expressions are found for the upper bound of the error probability of coherent receivers of M-PSK signals with a sinusoidal envelope for M = 2, 4, 8, 16, 32. A logarithmic measure of the relative increase in the probability of error compared to the case of no distortion is introduced. The functional dependence of this measure on the duration of sending the signal, the carrier frequency and the number of phases of the signal, as well as on the communication range and the signal-to-noise ratio is determined. On the plane of the carrier frequency, the duration of sending the signal, for each type of signal, a boundary of the region above which the signals are relatively invariant to frequency distortions in the marine environment is constructed. A comparison is made with the case of receiving M-PSK signals with a rectangular envelope. It is shown that invariant signals with a sinusoidal envelope have a shorter duration than signals with a straight-angle envelope. In addition, the duration of signals with a sinusoidal envelope is significantly less dependent on the number of phases of the signal.

UTD-Based Ray-Tracing MIMO Channel Modeling for the Next-Generation Communications Within Underground Tunnels

Limited work has previously been conducted into deterministic modeling of the 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> Generation (5G) millimeter (mm)-wave wireless communications within geometrically non-uniform tunnels. This study predicts and analyzes broadband Multiple–Input Multiple–Output (MIMO) propagation in underground mine tunnels for 5G communications and beyond. At extremely short wavelength, each rugged and uneven surface of the tunnel is modelled as a group of diffracting rectangular prism wedges. A deterministic Ray-Tracing (RT) MIMO model is developed based on the Uniform Theory of Diffraction (UTD). All predicted MIMO sub-channels have been successfully fitted with the experimental measurements. MIMO multipath fading of underground tunnels are found to be lognormally distributed and strongly depends on the tunnel’s size and shape.

Channel Characterization and Modeling for 6G UAV-Assisted Emergency Communications in Complicated Mountainous Scenarios.

Regarding the new demands and challenges of sixth-generation (6G) mobile communications, wireless networks are undergoing a significant shift from traditional terrestrial networks to space-air-ground-sea-integrated networks. Unmanned aerial vehicle (UAV) communications in complicated mountainous scenarios are typical applications and have practical implications, especially in emergency communications. In this paper, the ray-tracing (RT) method was applied to reconstruct the propagation scenario and then acquire the wireless channel data. Channel measurements are also conducted in real mountainous scenarios for verification. By setting different flight positions, trajectories, and altitudes, channel data in the millimeter wave (mmWave) band was obtained. Important statistical properties, such as the power delay profile (PDP), Rician K-factor, path loss (PL), root mean square (RMS) delay spread (DS), RMS angular spreads (ASs), and channel capacity were compared and analyzed. The effects of different frequency bands on channel characteristics at 3.5 GHz, 4.9 GHz, 28 GHz, and 38 GHz bands in mountainous scenarios were considered. Furthermore, the effects of extreme weather, especially different precipitation, on the channel characteristics were analyzed. The related results can provide fundamental support for the design and performance evaluation of future 6G UAV-assisted sensor networks in complicated mountainous scenarios.

Non-line-of-sight multiple reflection underwater wireless optical communications channel model based on a capillary waves rough sea surface.

In a non-line-of sight reflective underwater wireless optical communications (UWOC) link, the transmitted beam relies on reflections from the sea surface to propagate to the underwater receiver. Most previous research on reflective channels has sufficiently considered single reflections from a smooth or rough surface, while ignoring the effect of multiple reflections. In fact, a rough sea surface may cause the reflected photons to hit the sea surface again, which is referred as a multiple reflection process. To make up for deficiencies in the existing literature, we first construct a capillary waves rough sea surface model, and then present a multiple reflection channel model with the help of the Monte Carlo ray tracing approach. The path loss and channel impulse response (CIR) were further evaluated based on the model for different communications scenarios. Numerical results suggest that multiple reflections increase the path loss by more than about 5dB, and reduce the CIR amplitude to less than one-third compared to a single reflection. The work done in this paper aims to provide theoretical support for UWOC system design.

Simulation analysis of underwater wireless optical communication based on Monte Carlo method and experimental research in complex hydrological environment

This paper aims to address the challenges of short optical communication distances and high Bit Error Rates (BERs) caused by seawater absorption, scattering, and underwater turbulence. This paper establishes an optical communication channel model based on the Monte Carlo method and simulates and analyzes the process of received optical power attenuation when light is transmitted underwater due to absorption and scattering. The simulation model focuses on the influence of seawater type, transmission distance, receiver position, and angle on the received optical power attenuation. The results of this simulation will provide theoretical support for the development of prototype underwater optical communication systems and experiments in complex environments. To solve the long-range weak signal reception and processing issues in underwater optical wireless communication systems, this paper proposes the design and implementation of an underwater optical wireless communication system using optimized on-off keying high-power light-emitting diode/laser diode modulation technology and avalanche photodiode (APD)/photomultiplier (PMT) receiver modules. In addition, this paper describes the design of the underwater optical communication host computer software, which provides functions such as mode selection, BER monitoring, and file transfer. To test the performance of the proposed system, this paper conducts experiments in a 35 m long pool, fixed platform, and underwater mobile platform, as well as cross-air-water interface optical communication performance test experiments in a complex hydrological environment. The results show that the system achieved a 35 m underwater medium communication distance, transmission rate of 5–20 Mbps, and cross-domain wireless optical communication function under the condition of a BER of less than 10−6. The experiments also revealed that the communication distance decreases as the turbidity of the water body increases and the PMT receiver module selected at the receiver end has a longer communication distance than the APD receiver module. Overall, this paper demonstrates the feasibility of the proposed technology for underwater optical communication systems in complex waters, providing theoretical and data support for the next engineering practice.

Design and Performance Evaluation of Free Space Optical Communication Link in Zaria, Nigeria

Free Space Optical Communication (FSOC) is an optical technology with a great chance to complement traditional wireless communication technologies. It offers essential advantages compared to Radio Frequency (RF), such as low power consumption, no frequency restrictions, no electromagnetic interference, security, and a significant increase in bandwidth. Similarly, they have proven a worthy substitute for fiber optics with notable advantages. FSOC systems are usually installed above ground level and are therefore exposed to prevailing weather conditions such as haze, fog, rain, etc. which negatively affect the optical signal transmission. There is a shortage of research on using FSO systems in tropical regions. For this reason, accurate free space optical communication channel modeling helps telecommunication operators to engineer and appropriately manage their networks. Therefore, this research work developed Free Space Optical Communication Channel Model to mitigate the effects of atmospheric attenuations by estimating the specifically induced attenuation caused by both haze and rainfall rates on the FSOC link in the Zaria geographical area using two years of measured visibility data and rainfall rates data of the study location obtained from Nigerian Meteorological (NIMET) agency, Zaria station, locatedat the Nigeria College of Aviation Technology (NCAT) Zaria and Center for Energy Research and Training (CERT), Ahmadu Bello University (ABU), Zaria. The performance of the FSOC system is analyzed and evaluated through Link Margin (LM) analysis by using the design specifications of a commercial optical transceiver (TereScope 5000). The haze-induced attenuation obtained at 850nm, 950nm, and 1550nm is 5.934dB, 6.402dB, and 3.152dB respectively. Therefore, the result shows that the 1550 nm wavelength has minimum haze-induced attenuation compared to 850nm and 950nm at a propagation link distance of 6km. Furthermore, from the results of the performance evaluation of the LM analysis for the combined effects of Geometrical Attenuation (Gatt), Haze-Induced Attenuation (HIA), and Rain-Induced Attenuation (RIA), the result shows that operating a 1550nm wavelength in transmission power greatly improves optical transmission when compared with 850nm and 950nm wavelengths. Generally, the overall outcome of the research concludes that the free space optical communication system has the robustness to handle successful wireless communication during the worst weather conditions in Zaria throughout the year for a link range of up to 6km

Composite channel modeling for underwater optical wireless communication and analysis of multiple scattering characteristics.

In this study, we propose an innovative composite channel model that considers multi-size bubbles, absorption, and fading caused by scattering for investigating the effect of multiple scattering on the optical properties of a channel. The model is based on Mie theory, geometrical optics and the absorption-scattering model in the Monte-Carlo framework, and the performance of the optical communication system of the composite channel was analyzed for different positions, sizes, and number densities of bubbles. A comparison with the corresponding optical properties of conventional particle scattering indicated that a larger number of bubbles corresponded to greater attenuation of the composite channel, which was manifested by a low power at the receiver, an increased channel impulse response, and the observance of a prominent peak in the volume scattering function or critical scattering angles. Additionally, the effects of the position of large bubbles on the scattering property of the channel were investigated. The proposed composite channel model can provide reference data for designing a more reliable and comprehensive underwater optical wireless communication link.

Помехоустойчивость когерентного приема двоичных сигналов с синусоидальной огибающей в гидроакустическом канале связи

Goals. The main purpose of this work is to develop a methodology for determining the parameters of binary signals, at which the signals become relatively invariant to frequency distortions in the marine environment. The frequency distortion of the signals is caused by the uneven frequency response of the attenuation of the marine environment. The main part of this technique is to assess the effect of frequency distortion of signals on the noise immunity of reception. In accordance with this, the error probabilities of signal receivers with various types of manipulation are determined, which are optimal in the absence of distortion. Methods. The provisions of applied hydroacoustics, the theory of random processes and the theory of transmission of discrete messages are used. The main content. The paper considered a model of a single-beam sonar communication channel, characteristic of the deep sea, when the receiver or transmitter is located in the depths of the sea. The transmission coefficient of the channel is used as a transmission coefficient with a Gaussian amplitude -frequency response and a linear phase-frequency response. The error probabilities of coherent binary signal receivers with amplitude, frequency and phase manipulation with a sinusoidal envelope are determined. Coherent receivers optimal by the criterion of maximum likelihood under the action of white Gaussian noise and the absence of distortion in the marine environment are considered as receivers. A logarithmic measure of increasing the probability of error is introduced, which characterizes the deterioration of noise immunity due to frequency distortions in the channel. For some typical cases, the values of signal parameters that are relatively invariant to frequency distortions in the marine environment are determined. Results. Expressions of the error probability of coherent receivers of binary signals with amplitude, frequency and phase manipulation with a sinusoidal envelope are found. A logarithmic measure of the relative increase in the probability of error compared to the case of no distortion is introduced. The functional dependence of this measure on the duration of sending the signal, the carrier frequency and the initial phase of the signal, as well as on the communication range and the signal-to-noise ratio is determined. On the plane of the carrier frequency, the duration of the signal for each type of signal, the boundary of the region above which the signals are relatively invariant to frequency distortions in the marine environment is constructed, a comparison is made with the case of signals with a rectangular envelope. For communication ranges R = 1.5 km and 3 km and typical carrier frequencies, the minimum values of the duration of invariant signals are given.

A Unification of LoS, Non-LoS, and Quasi-LoS Signal Propagation in Wireless Channels

The modeling of wireless communication channels is often broken down into two distinct states, defined according to the optical viewpoints of the transmitter (TX) and receiver (RX) antennas, namely, line-of-sight (LoS) and non-LoS (NLoS). Movement of the TX, RX, both and/or objects in the surrounding environment means that channel conditions may transition between LoS and NLoS leading to a third state of signal propagation, namely, quasi-LoS (QLoS). Unfortunately, this state is largely ignored in the analysis of signal propagation in wireless channels. We, therefore, propose a new statistical framework that unifies signal propagation for LoS, NLoS, and QLoS channel conditions, leading to the creation of the three-state model (TSM). The TSM has a strong physical motivation, whereby the signal propagation mechanisms underlying each state are considered to be similar to those responsible for Rician fading. However, in the TSM, the dominant signal component, if present, can be subject to shadowing. To support the use of the TSM, we develop novel formulations for the probability density functions of the in-phase and quadrature components of the complex received signal, the received signal envelope, and the received signal phase. In addition, we derive an expression for the complex autocorrelation function of the TSM, which will be of particular importance in understanding and simulating its time correlation properties. Finally, we show that the TSM provides a good fit to field measurements obtained for two different body-centric wireless channels operating at 2.45 GHz, which are known to be subject to the phenomena underlying the TSM.

Channel Characterization and Ray-Tracing Assisted Stochastic Modeling for Urban Vehicle-to-Infrastructure Terahertz Communications

To support intelligent vehicular services, vehicular ad-hoc networks (VANET) require high-speed communications from vehicles to infrastructure (V2I). To meet such demands, the Terahertz (THz) band, with abundant spectrum resources, is envisioned as a promising solution. However, a premise problem is channel modeling for THz V2I communications. In this paper, ray-tracing (RT) techniques are utilized to analyze the V2I channel in an urban scenario at 300 GHz. Channel statistics, including path loss, shadow fading, etc, are thoroughly characterized. The parameters of multi-path components (MPCs) and similarity of MPCs existing on identical streets are analyzed and modeled. Furthermore, the birth and death processes of MPCs are carefully characterized and modeled. A new criterion, namely, the virtual transmitter position scheme, is proposed to determine the birth and death of MPCs and the evolution of MPCs during their lifetime. Based on this, a ray-tracing assisted stochastic channel model (RTA-SCM), is proposed, which combines the RT technique and stochastic processes. The effectiveness and accuracy of RTA-SCM are validated by comparing it against RT data and geometry-based stochastic models. The proposed model can be utilized in time-varying THz V2I communications.