Analysis of indoor THz communication systems with finite-bit DACs and ADCs

Zhang, Y., Li, D., Qiao, D. and Zhang, L. (2022) Analysis of indoor THz communication systems with finite-bit DACs and ADCs. IEEE Transactions on Vehicular Technology, 71(1), pp. 375-390. (doi: 10.1109/TVT.2021.3123380)

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Abstract

Terahertz (THz) communication is foreseen to be a key technology for the 6G wireless communications. In this paper, the performance of downlink Terahertz (THz) communication systems with low-resolution digital-to-analog converters (DACs) at the Access Point (AP) and/or finite-bit analog-to-digital converters (ADCs) at the user sides are investigated. Array-of-subarrays architecture is assumed at the AP, where each RF chain uniquely activates a disjoint subset of antennas, each of which is connected to an exclusive phase shifter. Hybrid precodings including maximum ratio transmission (MRT) and zero-forcing (ZF) precoding are considered. The best beamsteering direction for the phase shifters in the large subarray antenna regime is first proved to be the direction of the line-of-sight (LOS) path. Subsequently, the closed-form expression of the lower-bound of the achievable rate in the large subarray antenna regime is derived, which is the same for both MRT and ZF and is independent of the transmit power. Moreover, numerical results show that the rate loss caused by the phase uncertainties can be negligible in large subarray antenna regime and moderate resolution DACs and ADCs can achieve performance close to the infinite-resolution one. Numerical results validating the analysis are provided as well. Overall, the impact of finite-bit precoding and finite-bit ADCs on the achievable rate of indoor THz communication systems is characterized.

Item Type:Articles
Additional Information:This work is supported in part by the National Natural Science Foundation of China (61671205), in part by Shanghai Rising-Star Program (No. 21QA1402700) and also in part by the open research fund of National Mobile Communications Research Laboratory, Southeast University (No.2020D02).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Zhang, Professor Lei
Authors: Zhang, Y., Li, D., Qiao, D., and Zhang, L.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:IEEE Transactions on Vehicular Technology
Publisher:IEEE
ISSN:0018-9545
ISSN (Online):1939-9359
Published Online:27 October 2021
Copyright Holders:Copyright © 2021 IEEE
First Published:First published in IEEE Transactions on Vehicular Technology 71(1): 375-290
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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