University of Oulu

P. Kyösti, P. Zhang, A. Pärssinen, K. Haneda, P. Koivumäki and W. Fan, "On the Feasibility of Out-of-Band Spatial Channel Information for Millimeter-Wave Beam Search," in IEEE Transactions on Antennas and Propagation, vol. 71, no. 5, pp. 4433-4443, May 2023, doi: 10.1109/TAP.2023.3249837.

On the feasibility of out-of-band spatial channel information for millimeter-wave beam search

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Author: Kyösti, Pekka1,2; Zhang, Peize1; Pärssinen, Aarno1;
Organizations: 1Centre for Wireless Communications, University of Oulu, 90570 Oulu, Finland
2Keysight Technologies Finland Oy, 90630 Oulu, Finland
3Department of Electronics and Nanoengineering, Aalto University, 02150 Espoo, Finland
4Antenna, Propagation and Millimeter-Wave Systems Section, Department of Electronic Systems, Faculty of Engineering and Science, Aalborg University, 9220 Aalborg, Denmark
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.4 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2023
Publish Date: 2023-03-27


Prolonged beam alignment is the main source of overhead in mobile wireless communications at millimeter-wave (mm-wave) frequencies due to narrow beams following the requirement of high antenna gains. Out-of-band spatial information may be used in initial beam search when lower frequency band radios are operating in conjunction with mm-wave radios. The feasibility of using low-band channel information for coarse estimation of high-band beam directions strongly depends on the spatial congruence between the two frequency bands. In this work, we try to answer two related questions. First, how similar is the power angular spectrum (PAS) of propagation channels between two widely separated frequency bands? Then, what is the impact of practical antenna configurations on spatial channel similarity? We propose a beam directions based metric to assess the power loss and number of false directions if out-of-band spatial information is used instead of in-band information. This metric is more practical and useful than comparing the PASs directly. Point cloud ray tracing and propagation measurement results across multiple frequency bands and environments are used to show that the degree of spatial similarity of beamformed channels is related to antenna beam widths, frequency gap, and radio link conditions.

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Series: IEEE transactions on antennas and propagation
ISSN: 0018-926X
ISSN-E: 1558-2221
ISSN-L: 0018-926X
Volume: 71
Issue: 5
Pages: 4433 - 4443
DOI: 10.1109/TAP.2023.3249837
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was partly supported by the European Commission through the H2020 project Hexa-X (Grant no. 101015956) and partly by 6G Flagship programme, funded by Academy of Finland (Grant no. 346208).
EU Grant Number: (101015956) Hexa-X - A flagship for B5G/6G vision and intelligent fabric of technology enablers connecting human, physical, and digital worlds
Academy of Finland Grant Number: 346208
Detailed Information: 346208 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2023. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see