Research Project: Drerin Öğrenme Tabanlı Özgün Gelecek Nesil Haberleşme Sistemleri
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Contributors
Funders
ID
TB.00662
Authors
Başar, Ertuğrul
Faculty Member
Publications
Pairwise sequency index modulation with OTSM for green and robust single-carrier communications
(IEEE-Institute of Electrical and Electronics Engineers, 2024) Başar, Ertuğrul; Doosti-Aref, Abed; Masouros, Christos; Arslan, Huseyin; Department of Electrical and Electronics Engineering; Yes; College of Engineering
In this letter, inspired by the fundamental thoughts of sequency index modulation (SeIM) and orthogonal time sequency multiplexing (OTSM), a novel technique is introduced for green and robust single-carrier communications in wireless networks. More specifically, pairwise SeIM (PSeIM) is proposed as a novel indexing scheme making SeIM robust to error propagation and significantly reduces the peak power of SeIM-based systems with a lower complexity of detection. Analytical results are presented for the bit error rate (BER), peak-to-average power ratio (PAPR), and spectral efficiency to reveal the trade-off and advantages in PSeIM-OTSM. Simulation and analytical results verify that for 4-QAM uncoded data, PSeIM-OTSM outperforms OTSM by 50% in terms of both PAPR and complexity of detection along with 125.32% energy efficiency improvement to achieve a BER of 10-8 in high mobility doubly spread channels.
Quadrature noise modulation for robust and flexible communication
(Institute of Electrical and Electronics Engineers Inc., 2025) Altun, Ufuk; Başar, Ertuğrul; Altun, Ufuk; Department of Electrical and Electronics Engineering; CoreLab (Communications Research and Innovation Laboratory); Yes; College of Engineering; Laboratory
This letter introduces two novel noise modulation (NoiseMod) signaling schemes designed to enhance the bit rate of the classical binary NoiseMod (B-NoiseMod) approach. Quadrature NoiseMod (Q-NoiseMod) adds a new dimension to B-NoiseMod by utilizing two orthogonal noise bases to encode two bits per symbol, while mean-variance NoiseMod (MV-NoiseMod) exploits the statistical means of noise distributions as an additional symbol dimension. Closed-form theoretical bit error probability expressions are derived for all proposed schemes. Numerical simulations confirm that both Q-NoiseMod and MV-NoiseMod significantly outperform rate-equivalent B-NoiseMod, with MV-NoiseMod achieving an additional performance gain over Q-NoiseMod under AWGN channels.
A hybrid autoencoder and index modulation framework for OTFS modulation
(Springer, 2025) Başar, Ertuğrul; Tek, Yusuf İslam; Doğukan, Ali Tuğberk; Gevez, Yarkın; Pıhtılı, Mehmet Ertuğ; Doğukan, Ali Tuğberk; Tek, Yusuf İslam; Department of Electrical and Electronics Engineering; CoreLab (Communications Research and Innovation Laboratory); Yes; Pıhtılı, Mehmet Ertuğ; College of Engineering; Laboratory
This paper presents an innovative approach to orthogonal time frequency space (OTFS) modulation by integrating autoencoder-based enhanced (AEE) joint delay-Doppler index modulation (JDDIM) techniques. The proposed AEE-JDDIM-OTFS framework leverages deep learning to optimize the mapping and demapping processes, significantly improving spectral and energy efficiency in high-mobility communication scenarios. The system's performance is further enhanced by the introduction of a low-complexity greedy detector that maintains robust detection accuracy, even under imperfect channel state information (CSI) conditions. Extensive simulation results demonstrate that the proposed scheme achieves superior bit error rate (BER) performance compared to conventional OTFS and other OTFS-based modulation schemes, even in imperfect channel state information situations. The findings suggest that the AEE-JDDIM-OTFS framework offers a practical, low-complexity solution with promising potential for next-generation wireless communication systems.
A reinforcement learning-assisted OFDM-IM communication system against reactive jammers
(Institute of Electrical and Electronics Engineers Inc., 2024) Başar, Ertuğrul; Altun, Ufuk; Department of Electrical and Electronics Engineering; Laboratory; Yes; College of Engineering; CoreLab (Communications Research and Innovation Laboratory)
An innovative orthogonal frequency division multiplexing with index modulation (OFDM-IM) transmitter design is proposed in this paper to enable high-speed communication against reactive jammers. The proposed model can dynamically adjust its index modulation (IM) parameters and modulation types, including a novel multi-carrier noise modulation capability that enhances robustness under heavy jamming conditions. Moreover, a reinforcement learning (RL) mechanism is implemented to find the optimal defense strategy without needing any information about the jammer. To validate our approach, we conducted extensive computer simulations to evaluate the system's performance against various jammer types. Our simulation results revealed that subcarrier adaptation (adjusting IM parameters) enhances system performance towards higher throughput, while noise modulation improves bit error rate (BER) performance. Moreover, the results verify the model's ability to maintain robust communication in the presence of sophisticated reactive jamming attacks, outperforming several benchmark models. © 2015 IEEE.
Joint delay-Doppler index modulation for orthogonal time frequency space modulation
(IEEE-Inst Electrical Electronics Engineers Inc, 2024) Başar, Ertuğrul; Tek, Yusuf İslam; ; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; CoreLab (Communications Research and Innovation Laboratory); Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Laboratory
Orthogonal time frequency space (OTFS) is a promising waveform with outstanding performance in doubly-selective channels. Spreading information symbols across the entire delay-Doppler plane enables OTFS to exploit full diversity. Nevertheless, there is a need for enhanced reliability in OTFS systems to satisfy the rigorous requirements of forthcoming communication systems. To tackle this concern, we propose a scheme called joint delay-Doppler index modulation OTFS (JDDIM-OTFS). This scheme activates delay or Doppler resource elements in a subframe, and in order to obtain higher spectral efficiency, we use different constellations for each active resource block. Furthermore, we utilize a low-complex detector with the help of a greedy approach. Moreover, a theoretical upper bound is derived for the bit error rate (BER). Simulation results validate that JDDIM-OTFS outmatches classical OTFS and other benchmark schemes in terms of BER under perfect and imperfect channel conditions.
