Performance Analysis of Superimposed Pilot Channel Estimation for OTFS in Fractional Doppler Channels
34th Signal Processing and Communications Applications Conference, SIU 2026, İstanbul, Türkiye, 7 - 10 Temmuz 2026, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Doi Numarası: 10.1109/siu71813.2026.11636808
- Basıldığı Şehir: İstanbul
- Basıldığı Ülke: Türkiye
- Anahtar Kelimeler: Channel Estimation, Fractional Doppler, OTFS, Superimposed Pilot
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
Orthogonal Time Frequency Space (OTFS) modulation is a promising technology for 6G and beyond, as it overcomes severe Doppler shifts in high-mobility environments. However, physical channel paths introduce fractional Doppler shifts that cause inter-Doppler interference. Conventional pilot-based channel estimation mitigates this by transmitting pilots in time-multiplexed frames (block pilots), which degrades spectral efficiency. In this study, a Superimposed Pilot (SP) based channel estimation architecture for OTFS is implemented and evaluated against Block Pilot, Pseudo-Noise sequence, and Ideal Channel State Information methods. By overlaying the pilot directly onto the data across the delay-Doppler grid, the need for dedicated pilot time slots is eliminated. Simulation results under 3GPP Extended Vehicular A conditions at 500 km/h show that the SP scheme achieves higher throughput than the Block Pilot scheme while maintaining comparable reliability at high signal-to-noise ratio.