Abstract
In this paper, we consider a downlink (DL) massive multiple-input multiple-output (MIMO) system, where different users have different mobility profiles. To support this system, we propose to use a hybrid orthogonal time frequency space (OTFS)/orthogonal frequency division multiplexing (OFDM) modulation scheme, where OTFS is applied for high-mobility users and OFDM is used for low-mobility users. Two precoding designs, namely full zero-forcing (FZF) precoding and partial zero-forcing (PZF) precoding, are considered and analyzed in terms of per-user spectral efficiency (SE). With FZF, interference among users is totally eliminated at the cost of high computational complexity, while PZF can be used to provide a trade-off between complexity and performance. To apply PZF precoding, users are grouped into two disjoint groups according to their mobility profile or channel gain. Then, zero-forcing (ZF) is utilized for high-mobility or strong channel gain users to completely cancel the inter-group interference, while maximum ratio transmission (MRT) is applied for low-mobility users or users with weak channel gain. To shed light on the system performance, the SE for high-mobility and low-mobility users with a minimum-mean-square-error (MMSE)-successive interference cancellation (SIC) detector is investigated. Our numerical results reveal that the PZF precoding with channel gain grouping can guarantee a similar quality of service for all users. In addition, with mobility-based grouping, the hybrid OTFS/OFDM modulation outperforms the conventional OFDM modulation for high-mobility users.
Original language | English |
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Title of host publication | Proceedings of the IEEE Conference on Global Communications, GLOBECOM 2023 |
Publisher | Institute of Electrical and Electronics Engineers Inc. |
Number of pages | 6 |
ISBN (Electronic) | 9798350310900 |
ISBN (Print) | 9798350310917 |
DOIs | |
Publication status | Published - 26 Feb 2024 |
Event | IEEE Global Communications Conference 2023 - Kuala Lumpur, Malaysia Duration: 04 Dec 2023 → 08 Dec 2023 https://globecom2023.ieee-globecom.org/ |
Publication series
Name | GLOBECOM Proceedings |
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ISSN (Print) | 1930-529X |
ISSN (Electronic) | 2576-6813 |
Conference
Conference | IEEE Global Communications Conference 2023 |
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Abbreviated title | GLOBECOM 2023 |
Country/Territory | Malaysia |
City | Kuala Lumpur |
Period | 04/12/2023 → 08/12/2023 |
Internet address |