Channel estimation and data detection schemes for orthogonal time frequency space massive
Date
2022
Authors
Muzavazi, Rodwell
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Abstract
The desire to lower inter-carrier interference, achieve low pilot overhead and improve the performance in high-Doppler scenarios has led to much research in the orthogonal timefrequency space (OTFS) modulation scheme, which performs better than the orthogonal frequency division multiplexing modulation scheme. Fifth generation (5G) and future generation systems exploit the time diversity waveform nature of OTFS to increase the reliability of the wireless link. The information carrying symbols in OTFS are multiplexed into constant channels in the delay-Doppler domain.
In the quest to increase reliability, bandwidth efficiency, data throughput, and capacity in highDoppler scenarios, this research focuses on combining OTFS with massive multiple-input
multiple-output (MIMO). Due to the high mobility between transmitters and receivers in OTFS massive MIMO systems, there is a need to track the channel state information (CSI) as the
channel statistic changes frequently. To further improve the efficiency of OTFS massive MIMO systems, this research developed two channel estimation schemes that take advantage
of the sparsity nature of the system and a data detection scheme for the system. The proposed schemes are assessed using Normalized Mean Square Error (NMSE) and Bit-Error-Rate (BER) performance indexes to establish their efficiency in different scenarios.
The proposed channel estimation schemes are assessed by varying the base station antennas, pilot overhead ratio, Signal-Noise-Ratio (SNR), velocity, and the number of iterations to see
its NMSE performance compared to other schemes in the literature. On the other hand, the proposed data detection scheme is assessed by varying SNR values, the number of iterations
and the number of base station antennas to visualize its BER performance compared to other schemes in the literature. The results obtained from simulations prove that the proposed
channel estimation and data detection schemes perform optimally in the OTFS massive MIMO systems with low complexity costs. The performances of the proposed methods and the
associated low complexity costs make them more attractive for use in the OTFS massive MIMO-based 5G wireless communication systems.
Description
A dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering to the Faculty of Engineering and Built Environment, School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, 2022