Performance Analysis of RIS-Aided THz Wireless Systems over α-μ Fading: An Approximate Closed-Form Approach

Ngoc Phuc Le, Mohamed Slim Alouini

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

In this paper, we study a reconfigurable intelligent surfaces (RIS)-assisted Terahertz (THz) wireless systems with hardware impairments, where α-μ small-scale fading is considered for THz links in accordance with a recent measurement campaign. Firstly, we propose an accurate closed-form approximation of a weighted sum of cascaded non-identical α-μ variates based on the Gauss-Laguerre quadrature and a moment-matching method. This approximate approach facilitates analysis of the RIS-THz system over α-μ fading channels. To demonstrate, we derived closed-form expressions of the outage probability (OP), the ergodic capacity (EC), and the energy-efficiency (EE) of the system based on the proposed approximation. Secondly, we approximately characterize the end-to-end channel of the RIS-THz system when the number of RIS elements is large in scenarios with or without the presence of phase-shift errors. Based on this statistical characterization, the closed-form expressions of the OP, the EC, and the EE of the large-size RIS-THz system are obtained. Furthermore, we devise a low-complexity algorithm that jointly optimizes the transmit power and RIS element activation (i.e., ON/OFF RIS) to maximize the EE in the RIS-THz systems. This algorithm adopts an iterative dynamic programming approach for a maximum subarray problem (i.e., Kadane’s algorithm). Finally, simulations are provided to validate the accuracy of the theoretical analysis as well as demonstrate the efficacy of the devised algorithm.

Original languageEnglish (US)
Pages (from-to)1
Number of pages1
JournalIEEE Internet of Things Journal
Volume11
Issue number1
DOIs
StateAccepted/In press - 2023

Bibliographical note

Publisher Copyright:
IEEE

Keywords

  • Absorption
  • Array signal processing
  • energy efficiency
  • ergodic capacity
  • Hardware
  • outage probability
  • Power system reliability
  • Probability
  • Reconfigurable intelligent surface
  • Signal to noise ratio
  • Terahertz communications
  • Wireless communication
  • α-μ fading

ASJC Scopus subject areas

  • Signal Processing
  • Information Systems
  • Hardware and Architecture
  • Computer Science Applications
  • Computer Networks and Communications

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