Optimized Multicarrier Techniques for 5G Wireless Communications

Abstract

The increasing performance requirements of fifth-generation (5G) wireless communication systems have motivated the exploration of advanced multicarrier waveform candidates beyond conventional Orthogonal Frequency Division Multiplexing (OFDM). This work presents a comprehensive simulation-based performance analysis of OFDM, Filter Bank Multicarrier (FBMC), and Generalized Frequency Division Multiplexing (GFDM), including their Index Modulation (IM) variants, using bit error rate (BER) as the primary evaluation metric. A unified MATLAB framework is developed to model multicarrier transmission, modulation, filtering, channel effects, equalization, and demodulation under identical system parameters. The study evaluates system performance for different modulation orders, namely 32-QAM and 64-QAM, over additive white Gaussian noise (AWGN), Rician, and Rayleigh fading channels. The impact of prototype filters, overlapping factors, and roll-off parameters on FBMC and GFDM performance is investigated. In addition, index modulation is employed to enhance spectral efficiency by activating a subset of subcarriers, and its effect on BER performance is analyzed under various channel conditions. Furthermore, the trade-off between data rate and BER is examined for FBMC and GFDM at a fixed signal-to-noise ratio. Simulation results demonstrate that FBMC achieves improved BER performance due to superior spectral containment and reduced interference, while GFDM offers flexible waveform design at the cost of increased interference, particularly at higher modulation orders. The IM-based schemes show enhanced spectral efficiency with competitive BER performance compared to conventional multicarrier systems. The outcomes of this work provide valuable insights into waveform selection and design considerations for future wireless communication systems.

Introduction

The rapid growth of wireless communication demands higher data rates, better spectral efficiency, and reliable transmission under diverse channel conditions. Multicarrier modulation techniques such as OFDM, FBMC, and GFDM are widely used to combat multipath fading. While OFDM is simple to implement, it suffers from high out-of-band emissions, sensitivity to synchronization errors, and reduced spectral efficiency. FBMC improves spectral localization but increases system complexity, and GFDM offers flexible block-based transmission at the cost of self-interference at high data rates.

Index Modulation (IM) has emerged as a method to enhance spectral and energy efficiency by using subcarrier indices to carry additional information. Integrating IM with OFDM, FBMC, and GFDM improves bit error rate (BER), especially in fading channels.

Methodology: MATLAB simulations evaluate BER performance under AWGN, Rayleigh, and Rician fading channels for 32-QAM and 64-QAM modulation. Key steps include random bit generation, QAM modulation, multicarrier transmission (OFDM with CP, FBMC with filter banks, GFDM with block-based pulse shaping), channel effects, receiver processing, QAM demodulation, and BER computation.

Results:

• BER decreases with increasing SNR for all schemes.

• GFDM consistently outperforms OFDM and FBMC due to flexible pulse shaping and lower inter-carrier interference.

• Higher-order modulation (64-QAM) has higher BER than 32-QAM.

• AWGN channels provide the best BER, followed by Rician and Rayleigh.

• Lower GFDM roll-off factors improve BER, while higher values degrade it slightly.

• IM integration enhances BER across all multicarrier schemes.

• BER increases with higher data rates, but GFDM maintains superior performance at high throughput, making it suitable for 5G applications.

Conclusion

The BER performance of OFDM, FBMC, and GFDM multicarrier systems with and without index modulation was investigated using MATLAB simulations. The study evaluated system behavior under AWGN, Rayleigh, and Rician fading channels for different modulation orders and system parameters. The results indicate that FBMC achieves better BER performance than OFDM due to improved spectral containment, while GFDM offers greater flexibility at the expense of self-interference. Higher-order modulation schemes provide increased data rates but lead to degraded BER performance at low SNR values. Channel analysis shows that Rayleigh fading causes the most severe performance degradation, whereas AWGN yields the best results. The application of index modulation significantly improves BER performance by efficiently utilizing active subcarriers. The impact of roll-off factors on GFDM performance highlights the importance of proper filter design. The BER versus data rate analysis reveals a clear trade-off between throughput and reliability. Overall, the findings demonstrate that FBMC and GFDM-IM are strong candidates for future wireless communication systems requiring high spectral efficiency and flexibility.

References

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Copyright

Copyright © 2026 Govindu Swathi, Dr. P. Chandrasekhar Reddy . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.