Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios
Abstract
:1. Introduction
1.1. Related Work
1.2. Contributions
- An OTFS-based RAP waveform is designed for cellular communication systems. The RAP consisting of chirp sequences is mapped onto the delay axis in the DD domain, and the set of available RAPs is generated by applying distinct cyclic shifts to a root sequence.
- A novel RAP detection and TA estimation scheme for OTFS systems is proposed. At the BS, the received RAP signals superimposed by multiple UEs are transformed into the DD domain and combined through Doppler diversity. Subsequently, the detection function is obtained by performing a cross-correlation operation in FrFD between the cyclically shifted received sequence and the original root sequence. Finally, the peak of the detection function is utilized to detect the access UEs and estimate the corresponding TAs. Furthermore, we derive the detection threshold according to a specified desired probability of a false alarm. Among them, the Doppler diversity strategy and cross-correlation operation in FrFD are the core innovations of the proposed scheme.
- The performance of the proposed RAP detection and TA estimation scheme is evaluated in static, low-speed, medium-speed, and high-speed scenarios, which proves its robustness to Doppler shifts. In addition, we evaluate the performance when the number of UEs attempting to access simultaneously varied and all exhibit superior performance.
2. System Model and Random Access Preamble Design
2.1. System Model
2.2. Random Access Preamble Design
3. Proposed Access UE Detection and TA Estimation Algorithm
4. Simulation Results
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
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Parameter | Value |
---|---|
Size of an OTFS frame () | (512, 5) |
Subcarrier spacing () | 3 kHz |
Symbol duration (T) | 0.33 ms |
Frame duration () | 1.65 ms |
Chirp length () | 359 |
Chirp center frequency () | 5 MHz |
Chirp rate () | 1.643 × 109 |
Cyclic shift offset () | 20 |
RAP number () | 17 |
Doppler diversity number () | 5 |
Channel model | EVA |
Maximum Doppler shift () | 0 Hz, 300 Hz, 600 Hz, 1200 Hz |
UE number (Q) | 2, 4, 8 |
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Geng, X.; Zhu, N.; Chen, Z.; Ci, C.; Wang, Z.; Wu, H. Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios. Electronics 2024, 13, 1166. https://doi.org/10.3390/electronics13071166
Geng X, Zhu N, Chen Z, Ci C, Wang Z, Wu H. Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios. Electronics. 2024; 13(7):1166. https://doi.org/10.3390/electronics13071166
Chicago/Turabian StyleGeng, Xue, Ning Zhu, Zhuo Chen, Cheng Ci, Zonglian Wang, and Hong Wu. 2024. "Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios" Electronics 13, no. 7: 1166. https://doi.org/10.3390/electronics13071166
APA StyleGeng, X., Zhu, N., Chen, Z., Ci, C., Wang, Z., & Wu, H. (2024). Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios. Electronics, 13(7), 1166. https://doi.org/10.3390/electronics13071166