Engineering:Orthogonal Time Frequency and Space (OTFS)
Orthogonal Time Frequency Space is a 2D modulation technique that transforms the information carried in the Delay-Doppler coordinate system. The information is transformed in the similar time-frequency domain as utilized by the traditional schemes of modulation such as TDMA, CDMA, and OFDM.[1]
Overview
OTFS is a modulation scheme where each transmitted symbol experiences a near-constant channel gain even in channels at high carrier frequencies (mm-wave) or with high Doppler. OTFS essentially performs modulation in the Zak domain (also known as the delay-Doppler domain).[2]
It effectively transforms the time-varying multipath channel into a 2D channel in the delay-Doppler domain. Using this transformation, along with equalization within this domain, each symbol experiences similar channel gain throughout the transmission.[3]
The modulation begins with first mapping the information symbols x[k,l] in the delay–Doppler domain to symbols X [n, m] for creating the time-domain signal s(t) which is transmitted over a wireless channel. At the receiver end, the time-domain signal r(t) is mapped to the domain of time-frequency using the Winger transform which is the inverse of Heisenberg transform and then for symbol demodulation uses the delay–Doppler domain.[4]
Application
OTFS offers several advantages in particular environments where the dispersion is at high frequency. Environments such as these are encountered in mm-wave systems, due to both larger Doppler spreads and higher phase noise.[5]
References
- ↑ Monk, Anton; Hadani, Ronny; Tsatsanis, Michail; Rakib, Shlomo (2016-08-09). "OTFS - Orthogonal Time Frequency Space". arXiv:1608.02993 [cs.IT].
- ↑ Hadani, R.; Rakib, S.; Tsatsanis, M.; Monk, A.; Goldsmith, A. J.; Molisch, A. F.; Calderbank, R. (March 2017). "Orthogonal Time Frequency Space Modulation". 2017 IEEE Wireless Communications and Networking Conference (WCNC): 1–6. doi:10.1109/WCNC.2017.7925924. ISBN 978-1-5090-4183-1.
- ↑ Raviteja, P; T Phan, Khoa; Hong, Yi; Viterbo, Emanuele (2018). "Interference Cancellation and Iterative Detection for Orthogonal Time Frequency Space Modulation". IEEE Transactions on Wireless Communications 17 (10): 6501–6515. doi:10.1109/TWC.2018.2860011. https://ecse.monash.edu/staff/eviterbo/papers/twc18Raviteja.pdf.
- ↑ Farhang, Arman; RezazadehReyhani, Ahmad; Doyle, Linda E.; Farhang-Boroujeny, Behrouz (June 2018). "Low Complexity Modem Structure for OFDM-Based Orthogonal Time Frequency Space Modulation". IEEE Wireless Communications Letters 7 (3): 344–347. doi:10.1109/LWC.2017.2776942. ISSN 2162-2345.
- ↑ Hadani, R.; Rakib, S.; Molisch, A. F.; Ibars, C.; Monk, A.; Tsatsanis, M.; Delfeld, J.; Goldsmith, A. et al. (June 2017). "Orthogonal Time Frequency Space (OTFS) modulation for millimeter-wave communications systems". 2017 IEEE MTT-S International Microwave Symposium (IMS): 681–683. doi:10.1109/MWSYM.2017.8058662. ISBN 978-1-5090-6360-4.
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