University of Oulu

P. Jayasinghe, A. Tölli, J. Kaleva and M. Latva-Aho, "Traffic Aware Beamformer Design for Flexible TDD-Based Integrated Access and Backhaul," in IEEE Access, vol. 8, pp. 205534-205549, 2020, doi: 10.1109/ACCESS.2020.3037814

Traffic aware beamformer design for flexible TDD-based integrated access and backhaul

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Author: Jayasinghe, Praneeth1; Tölli, Antti1; Kaleva, Jarkko2;
Organizations: 1Center for Wireless Communications, University of Oulu, 90570 Oulu, Finland
2Solmu Technologies Oy, 90620 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2020
Publish Date: 2021-01-18


Integrated access and backhaul (IAB) network consists of base station (BS), relay nodes (RNs), and user-equipments (UEs), where BS and RNs exchange UE data via wireless in-band backhaul while sharing the same frequency-time resources with access links. In this paper, a flexible time-division-duplex (TDD)-based IAB network is considered where RNs and BS are assigned to distinct uplink (UL) or downlink (DL) transmission modes to mitigate conventional half-duplex (HD) loss at RNs. An iterative beamformer design is proposed to manage the resulting cross-channel interference and to allocate wireless backhaul and access resources jointly over two consecutive data delivery intervals required for communications between the BS and UEs through HD RNs. Dynamic traffic behavior is handled via weighted queue minimization objective, and user-specific UL/DL queues are also introduced at RNs to guarantee reliable end-to-end data delivery. Bi-directional forward-backward training via spatially precoded over-the-air pilot signaling is employed to allow decentralized beamformer design across all the nodes. A novel user allocation method is proposed to assign UEs to BS or RNs based only on long-term channel statistics and some practical IAB limitations. The numerical examples illustrate the superior system performance of the considered flexible IAB in comparison to the conventional HD relaying system.

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Series: IEEE access
ISSN: 2169-3536
ISSN-E: 2169-3536
ISSN-L: 2169-3536
Volume: 8
Pages: 205534 - 205549
DOI: 10.1109/ACCESS.2020.3037814
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported in part by the European Commission in the framework of the H2020-EUJ-02-2018 Project under Grant 815056 (5G-Enhance), and in part by the Academy of Finland under Grant 318927 (6Genesis Flagship).
EU Grant Number: (815056) 5G-Enhance - 5G Enhanced Mobile Broadband Access Networks in Crowded Environments
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
Copyright information: © The Authors 2020. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see