Joint Beamforming Optimization for IRS-aided THz Communication With Time Delays

Fei Zhao, Wanming Hao, Xiaobei You, Yi Wang, Zheng Chu, Pei Xiao

Research output: Journal PublicationArticlepeer-review


Intelligent reflecting surface (IRS)-aided terahertz (THz) communication has been regarded as a promising technology for future wireless networks. However, IRS generally suffers from the severe beam squint problem due to the frequency independent characteristic of IRS elements, especially for the ultra-wide THz frequency. To deal with this issue, we apply time delays to IRS, and formulate the weighted sum rate maximization problem via joint optimization of the base station beamforming as well as IRS reflection coefficients and time delays. To solve it, we propose an alternate optimization algorithm to divide the original optimization problem into three subproblems. The successive convex approximation, semidefinite relaxation, fractional programming and majorization minimization techniques are, respectively, applied to obtain the solution of each subproblem. Next, by alternatively solving these three subproblems until convergence, and solutions of the original problem are obtained. Simulation results illustrate that our proposed time delay-based IRS scheme can effectively mitigates the beam squint effect and achieve a better system performance compared to the conventional scheme.

Original languageEnglish
Pages (from-to)1
Number of pages1
JournalIEEE Wireless Communications Letters
Publication statusAccepted/In press - 2023
Externally publishedYes


  • Array signal processing
  • beam squint
  • Delay effects
  • Fading channels
  • IRS
  • OFDM
  • Optimization
  • Reflection
  • Signal to noise ratio
  • Terahertz
  • time delay

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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