A Survey of OTFS-Based Index Modulation Techniques: Challenges, Benefits, and Future Directions for 6G and Beyond
IEEE Open Journal of the Communications Society, 2026 (ESCI, Scopus)
- Yayın Türü: Makale / Derleme
- Basım Tarihi: 2026
- Doi Numarası: 10.1109/ojcoms.2026.3741396
- Dergi Adı: IEEE Open Journal of the Communications Society
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus, Compendex, INSPEC, Directory of Open Access Journals
- Anahtar Kelimeler: 6G, code index modulation, delay-Doppler, index modulation, media-based modulation, Orthogonal time frequency space, quadrature spatial modulation, space shift keying, spatial modulation, wireless communication systems
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
Orthogonal time frequency space (OTFS) is a two-dimensional modulation technique that uses the delay-Doppler (DD) domain and is a candidate for providing robust, high-capacity wireless communications for envisioned sixth-generation (6G) and beyond networks. The OTFS technique maps data to the DD domain instead of the traditional time-frequency domain, enabling it to fully utilize channel diversity and transform fast time-varying channels into nearly static channels. Index modulation (IM) is a communication paradigm that conveys information not only through conventional modulation symbols but also by encoding data bits in the indices of the selected communication resources to improve error performance, spectral efficiency, and energy efficiency. In this survey article, a review of work on OTFS-based wireless communication systems is presented. In particular, the existing OTFS-based IM (OTFS-IM) schemes in the literature are reviewed and systematically categorized according to their system architectures, detection methods, and performance aspects such as capacity, peak-to-average power ratio (PAPR), diversity, complexity, imperfect channel state information (CSI), spectral efficiency, and outage probability. Furthermore, the operating principles and system models of various OTFS-IM variants are described, followed by a comparative performance analysis in terms of computational complexity, error performance, capacity, energy savings, spectral efficiency, and throughput. Finally, the challenges, benefits, and future directions for OTFS-IM systems are discussed, covering key aspects such as complexity, efficiency, latency, channel estimation, hardware constraints, synchronization, security, and potential integration with other advanced wireless communication techniques.