This repository provides a Matlab-based framework to perform numerical analysis on channel models obtained upon combining small-scale fading and antenna misalignment effects. This analysis can also be verified using Monte-Carlo Simulations. We have also included code to particularly work with the Fluctuating Two Ray (FTR distribution), which is a recent addition to the channel models of Terahartz Wireless Systems. To use this code, clone this repository to your project folder.
A recent measurement campaign was conducted to measure the THz channel with operation at 304.2 GHz and 8 GHz bandwidth. Gradient descent was used to fit the distribution parameters for Gaussian, Rician, Nakagami-m and FTR distributions. FTR distribution performed a much better fit than other models. Morever, FTR distribution is a generalization of a lot more commonly used probability distributions for small scale fading.
The small-scale fluctuations in the amplitude of a signal transmitted over a wireless channel can be modeled by the superposition of a set of N dominant waves, referred to as specular components, to which other diffusely propagating waves are added.
X + jY is a complex Gaussian random variable, such that X and Y follow a Normal distribution with zero mean and standard deviation sigma. The random phase follows a Uniform distribution between zero and 2 pi. The amplitudes Vn are constants.
- get_ftr_pdf.m : Returns a function handle to the FTR PDF. Can be used to verify integrals and for numerical analysis.
- get_combined_pdf.m : Returns a function handle to the Combined FTR + Misalignment errors PDF.
- d_calc.m : Helper function to calculate the value of d as given in the FTR Probability Distribution expression above.
- my_asso_legendre_func.m : This function is be used to calculate Associated Legendre function for real parameters and complex argument. [For details, refer to I. S. Gradshteyn and I. M. Ryzhik, Table of Integrals, Series, and Products, 7th ed. Academic Press, 2007.]
- THz_Pathloss.m : Helper function to calculate the deterministic path loss due to molecular absorption.
- randpdf.m : Helper function to generate pseudo-random numbers from a user defined distribution. [Credits: Adam Nies³ony, Opole University of Technology, Poland]
- get_hf_thz.m : Helper function to generate pseudo-random numbers from the FTR distribution. This is an efficient alternative to randpdf.m, particularly for FTR Monte-Carlo simulations. [For details, refer to J. M. Romero-Jerez, F. J. Lopez-Martinez, J. F. Paris, and A. J. Goldsmith, “The fluctuating two-ray fading model: Statistical characterization and performance analysis,” IEEE Trans. Wireless Commun., vol. 16, no. 7, pp. 4420–4432, Jul. 2017.]
- Combined_thz_experiment.m : A sample virtual experiment to demonstrate the use of all the above functions. Feel free to make changes as required for your own purpose.
Atharva Anand Joshi, Undergraduate Student
Pranay Bhardwaj, PhD Researcher
Dr S. M. Zafaruddin, Senior Member, IEEE
Birla Institute of Technology and Science, Pilani