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Low-Dimensional Subspace Estimation of Continuous-Doppler-Spread Channel in OTFS Systems.
- Source :
-
IEEE Transactions on Communications . Jul2021, Vol. 69 Issue 7, p4717-4731. 15p. - Publication Year :
- 2021
-
Abstract
- Orthogonal time frequency space (OTFS) has shown to be a promising modulation technology that achieves the robust wireless transmission in high-mobility environments. The high mobility incurred Doppler effect in OTFS system, is represented as a continuous and relatively large band in the Doppler frequency. It yields the equivalent channel responses (ECRs) in the system change significantly within one symbol block, posing a challenge to channel estimation (CE) or tracking. In order to tackle this issue, in this paper, a set of transform-domain basis functions is designed to span a low-dimensional subspace for modeling the OTFS channel. Then, the CE can be performed by estimating a few projection coefficients of ECRs in the developed subspace, with training pilots. According to the individual transmission characteristic of OTFS signal, we propose a corner-inserted pilot pattern, which targets the low pilot overhead and satisfactory CE performance. Moreover, an OTFS signal detector, leveraging the time-domain channel equalization, linear-complexity interference cancellation and delay-Doppler domain maximal ratio combining detection, is developed to retrieve the transmitted data symbols. The simulations show the precisely estimated ECRs enable the detector to ideally demodulate 256-ary quadrature amplitude modulation signaling, under a velocity of 550 km/h at 5.9 GHz carrier frequency. [ABSTRACT FROM AUTHOR]
- Subjects :
- *DOPPLER effect
*CHANNEL estimation
*QUADRATURE amplitude modulation
Subjects
Details
- Language :
- English
- ISSN :
- 00906778
- Volume :
- 69
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Communications
- Publication Type :
- Academic Journal
- Accession number :
- 153068701
- Full Text :
- https://doi.org/10.1109/TCOMM.2021.3072744