International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 10 | Oct 2025
p-ISSN: 2395-0072
www.irjet.net
Performance Analysis of a 4×4 MIMO-OFDM Wireless Communication System using MMSE Equalization and Pilot-Based LS Channel Estimation Akshat Gupta Student , Department of Electronics and Communication Engineering , JSSATE Noida , U.P. , India ---------------------------------------------------------------------***--------------------------------------------------------------------
Abstract - This paper presents a MATLAB-based simulation and performance analysis of a 4×4 MIMO-OFDM wireless communication system employing QPSK modulation. The system operates under frequency-selective Rayleigh fading channels and incorporates pilot-based LS channel estimation and MMSE equalization. Key performance metrics, including Bit Error Rate (BER), average system capacity, and per-subcarrier SNR/capacity, are evaluated across a range of SNR values. The results provide a practical benchmark for future 5G/6G system simulations and education. MATLAB implementation: https://github.com/akshat-137/ 4x4-MIMO-OFDM-Wireless-Communication-System-Simulation Key Words: MIMO, OFDM, LS Channel Estimation, MMSE, MATLAB, Wireless Communication, 5G
1.INTRODUCTION Orthogonal Frequency Division Multiplexing (OFDM) is widely adopted in modern wireless communication systems due to its robustness against multipath fading and efficient spectral utilization. Multiple-Input Multiple-Output (MIMO) technology leverages multiple transmit and receive antennas to enhance link reliability and spectral efficiency. The combination of MIMO with OFDM forms the backbone of 4G LTE, 5G NR, and emerging 6G systems. This study simulates a 4×4 MIMO-OFDM system in MATLAB. The system incorporates: • Pilot-based LS channel estimation for accurate channel characterization. • MMSE equalization to mitigate noise and inter-symbol interference. The simulation evaluates: • Bit Error Rate (BER) versus SNR. • Average system capacity across subcarriers. • Per-subcarrier SNR and capacity distributions
2. SYSTEM MODEL 2.1 Block Diagram
Fig. 1 : Block diagram of 4×4 MIMO-OFDM system © 2025, IRJET
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