Bit Error Rate and Performance Analysis of Multi-User OTFS Under Nakagami-m Fading for 6 G and Beyond Networks
IEEE Transactions on Vehicular Technology, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1109/tvt.2026.3722067
- Dergi Adı: IEEE Transactions on Vehicular Technology
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Compendex, INSPEC, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: bit error rate, diversity order, Erlang distribution, fractional delay-Doppler, multi-user analysis, Nakagami-m fading, OTFS modulation
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
Orthogonal time frequency space (OTFS) modulation is a promising waveform for sixth-generation (6 G) and high-mobility wireless systems, where reliable error-performance characterization is essential. In this article, the bit error rate (BER) of OTFS over Nakagami-m fading is analyzed for the four practical variants, namely cyclic-prefix OTFS (CP-OTFS), zero-padded OTFS (ZP-OTFS), reduced cyclic-prefix OTFS (RCP-OTFS), and reduced zero-padded OTFS (RZP-OTFS). Using the delay-Doppler (DD) input-output relations, a closed-form BER is derived under maximal-ratio combining (MRC) detection by characterizing the MRC-combined signal-to-noise ratio (SNR) through Erlang statistics and the partial-fraction expansion of the product Erlang moment-generating function (MGF). The asymptotic diversity order is shown to equal the sum of the fading parameters over the resolvable paths and is contrasted with the unit diversity of uncoded orthogonal frequency-division multiplexing (OFDM). The framework is extended to fractional DD channels through effective power parameters that capture the fractional Doppler and delay effects, and to the multi-user uplink with co-channel interference, for which the average BER is obtained in integral-free form using the Kummer confluent hypergeometric function and the associated error floor is derived in closed form. A parametric analysis further quantifies how the effective diversity order scales with the interference loading. The analyses are validated through Craig's integral and Monte Carlo simulations, and the results illustrate the effects of the path count, fading severity, modulation order, and number of interfering users, together with the robustness of OTFS relative to OFDM in high-mobility settings.