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Agwu, O. E.
Department of Electrical and Electronic Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria
Odo, K. O.
Department of Electrical and Electronic Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria
Bekee, P. I.
Transmission Company of Nigeria, Aba 132KV Station, Abia State, Nigeria
Josiah, C.
Department of Electrical and Electronic Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria
ABSTRACT
The research paper evaluates how an Intelligent
Reflecting Surface (IRS)-assisted Orthogonal Frequency Division Multiplexing
(OFDM) system performs when transmitting over frequency-selective fading
channels with adaptive per-subcarrier phase-shift optimization. The receiver
uses an adaptive phase-shift optimization algorithm, enabling it to combine
reflected and directly received signals. The system evaluation was conducted
via Monte Carlo simulations that tested 64 subcarriers with 32 IRS elements,
using QPSK modulation and 4-tap frequency-selective channels. The system performance
metrics are measured through Bit Error Rate (BER) and spectral efficiency
tests, which operate under imperfect Channel State Information (CSI) and
Additive White Gaussian Noise (AWGN). The simulation results show that the
proposed optimized IRS configuration achieves better performance than both
conventional OFDM systems without IRS and IRS-assisted systems that use random
phase shifts. At 20 dB SNR, the proposed optimized IRS configuration
achieves a BER of 0.008, which is 16 times lower than the random IRS
configuration and 21 times lower than conventional OFDM. At 25 dB SNR, the spectral efficiency reaches
approximately 7.0 bps/Hz, representing a gain of 2.5 bps/Hz over the random IRS
configuration and 2.8 bps/Hz over conventional OFDM. The implementation
of adaptive per-subcarrier IRS phase optimization in broadband multicarrier
communication systems enables the significant improvements in reliability and
capacity enhancements for upcoming wireless networks.
Keywords: Intelligent Reflecting Surface, Orthogonal Frequency Division Multiplexing, Frequency-Selective Fading, Adaptive Phase Optimization, Spectral Efficiency, Bit Error Rate
https://doi.org/10.33922/j.ujet_v12i2_1
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Published
Sunday, May 03, 2026
Issue
Vol. 12, No. 2, June 2026
Article Section
GENERAL
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