6G sistemleri için OCDM performansının farklı sönümlü ve kusurlu kanal bilgisi altında BER analizi

Öz

Bu makale, Rayleigh, Rician, Nakagami-m (m=2), Weibull ve Jakes olmak üzere farklı sönümlemeli kanal modellerini kullanarak dikgen chirp bölmeli çoğullama (OCDM) sistemlerinin bit hata oranı (BER) performansına ilişkin bir araştırmayı sunmaktadır. Çalışma, sıfır zorlama (ZF), minimum ortalama karesel hata (MMSE) ve maksimum olasılık (ML) olmak üzere üç dedektör yapısı üzerinde gerçekleştirilmiştir. Ayrıca, çalışma farklı modülasyon türleri ve kusurlu kanal durumu bilgisinin (CSI) etkisini de içermektedir. Simülasyon sonuçları, Rician kanalının güçlü bir görüş hattı (LOS) bileşeni sayesinde tutarlı bir şekilde en iyi BER performansını sağladığını göstermektedir. Ayrıca, Jakes Doppler sönümleme kanalında, ML dedektörü MMSE ve ZF’ye kıyasla üstün BER performansı elde eder; MMSE, özellikle düşük ve orta SNR değerlerinde ZF'ye göre tutarlı bir ara kazanç sağlar. Kusurlu CSI'nın yüksek sinyal gürültü oranında (SNR) önemli hata tabanları oluşturduğunu da belirtmek önemlidir. Son olarak, yüksek modülasyon derecelerinin önemli ölçüde yüksek SNR gereksinimleri getirdiği tespit edilmiştir.

Anahtar Kelimeler

• OCDM
• Nakagami-m
• Weibull
• Jakes
• Kusurlu CSI.

A comprehensive BER analysis of OCDM under heterogeneous fading channels and imperfect CSI for 6G systems

Öz

The paper presents a investigation into the bit error rate (BER) performance of orthogonal chirp division multiplexing (OCDM) systems, utilising fading channel models such as Rayleigh, Rician, Nakagami-m (m=2), Weibull, and Jakes Doppler. The analysis is conducted across three receiver structures which are zero forcing (ZF), minimum mean square error (MMSE), and maximum likelihood (ML). Furthermore, the work extends to different modulation type and the effect of imperfect channel state information (CSI). The results of the simulation demonstrate that the Rician channel has been shown to consistently yield the best BER performance owing to a strong line of sight (LOS) component. Furthermore, under the Jakes Doppler fading channel, ML detection achieves superior BER performance compared to MMSE and ZF receivers, with MMSE providing a consistent intermediate gain over ZF, particularly at low to moderate SNR values. It is also important to note that imperfect CSI introduces significant error floors at high signal to noise ratio (SNR). Finally, it has been established that higher modulation orders impose substantially greater SNR requirements.

Anahtar Kelimeler

• OCDM
• Nakagami-m
• Weibull
• Jakes
• Imperfect CSI.

Kaynakça

1. E. Dahlman, S. Parkvall, and J. Skold, 5G NR: The next Generation Wireless Access Technology. Academic Press, 2nd ed., 2020.
2. X. Ouyang and J. Zhao, “Orthogonal chirp division multiplexing,” IEEE Transactions on Communications, 64 (9), 3946-3957, 2016. https://doi.org/10.1109/-TCOMM.2016.2594792.
3. M. S. Omar and X. Ma, “Performance analysis of OCDM for wireless communications,” IEEE Transactions on Wireless Communications, 20 (7), 4032-4043, 2021. https://doi.org/10.1109/ TWC.2021.3055070.
4. C. Browning, D. Dass, P. Townsend, X. Ouyang, “Orthogonal chirp-division multiplexing for future converged optical/millimeter-wave radio access networks,” IEEE Access, 10, 3571-3579, 2021. https://doi.org/ 10.1109/ACCESS.2021.3137716.
5. Y. Kim and H. Lee, “Orthogonal chirp-based frequency division multiplexing for short transmission time interval underwater communications,” Applied Acoustics, 231, 2025. https://doi.org/10.1016/j-apacoust.2025.110554.
6. Y. Liu, H. Zhao, H. Yao, Z. Hu, Y. Cui, and D. Wan, “Generalized orthogonal chirp division multiplexing in doubly selective channels,” IEEE Internet of Things Journal, 12 (12), 18495-18507, 2024. https://doi.org/ 10.1109/JIOT.2024.3522194.
7. X. Wang, Z. Jiang, and X. H. Shen, “Low complexity equalization of orthogonal chirp division multiplexing in doubly-selective channels,” Sensors, 20 (11), 3125, 2020. https://doi.org/10.3390/s20113125.
8. Y. Liu, F. Ji, M. Wen, and H. Qing, “Message-passing receiver for OCDM over multi-lag multi-doppler channels”, arXiv preprint arXiv:2401.04358, Jan. 2024.

9. I. Aboharba, H. Boud, Q. M. Rahman, R. K. Rao, “Performance analysis of a low-complexity detection for OFDM index modulation over Nakagami-m fading,” In 2017 IEEE 30th Canadian Conference on Electrical and Computer Engineering (CCECE), pp. 1-4, Windsor, ON, Canada, 2017.
10. H. M. Shwetha and S. Anuradha, “Performance analysis of novel index modulation-based non-orthogonal multiple access systems over Nakagami-m fading channels with imperfect CSI,” Radioengineering, 32 (3), 425-437, 2023. https://doi.org/10.13164/re.2023.0425.
11. J. Cheng, C. Tellambura, and N. C. Beaulieu, “Performance analysis of digital modulations on Weibull fading channels,” in Proc. IEEE VTC 2003-Fall, 1, pp. 236-240, Orlando, FL, USA, 2003.
12. A. J. Bamisaye and T. Quazi, “Media-based single-input multiple-output quadrature spatial modulation with imperfect channel estimation,” Heliyon, 10 (15), p. e35713, Aug. 2024. https://doi.org/ 10.1016/j.heliyon-2024.e35713.
13. A. Riadi, M. Boulouird, and M. M. Hassani, “ZF and MMSE detectors performances of a massive MIMO system combined with OFDM and M-QAM modulation,” Wireless Personal Communications, 116 (4), 3261-3276, 2021. https://doi.org/ 10.1007/s11277-020-07848-4.