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Random Access Identifier-Linked Receiver Beamforming with Transmitter Filtering in TDD-Based Random Access

Yuto MUROKI, Yotaro MURAKAMI, Yoshihisa KISHIYAMA, Kenichi HIGUCHI

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Summary :

This paper proposes a novel random access identifier (RAID)-linked receiver beamforming method for time division duplex (TDD)-based random access. When the number of receiver antennas at the base station is large in a massive multiple-input multiple-output (MIMO) scenario, the channel estimation accuracy per receiver antenna at the base station receiver is degraded due to the limited received signal power per antenna from the user terminal. This results in degradation in the receiver beamforming (BF) or antenna diversity combining and active RAID detection. The purpose of the proposed method is to achieve accurate active RAID detection and channel estimation with a reasonable level of computational complexity at the base station receiver. In the proposed method, a unique receiver BF vector applied at the base station is linked to each of the M RAIDs prepared by the system. The user terminal selects an appropriate pair comprising a receiver BF vector and a RAID in advance based on the channel estimation results in the downlink assuming channel reciprocity in a TDD system. Therefore, per-receiver antenna channel estimation for receiver BF is not necessary in the proposed method. Furthermore, in order to utilize fully the knowledge of the channel at the user transmitter, we propose applying transmitter filtering (TF) to the proposed method for effective channel shortening in order to increase the orthogonal preambles for active RAID detection and channel estimation prepared for each RAID. Computer simulation results show that the proposed method greatly improves the accuracy of active RAID detection and channel estimation. This results in lower error rates than that for the conventional method performing channel estimation at each antenna in a massive MIMO environment.

Publication
IEICE TRANSACTIONS on Communications Vol.E105-B No.12 pp.1548-1558
Publication Date
2022/12/01
Publicized
2022/05/25
Online ISSN
1745-1345
DOI
10.1587/transcom.2021EBP3193
Type of Manuscript
PAPER
Category
Wireless Communication Technologies

Authors

Yuto MUROKI
  Tokyo University of Science
Yotaro MURAKAMI
  Tokyo University of Science
Yoshihisa KISHIYAMA
  NTT DOCOMO, INC.
Kenichi HIGUCHI
  Tokyo University of Science

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