University of Oulu

R. Hashemi, S. Ali, N. H. Mahmood and M. Latva-Aho, "Joint Sum Rate and Blocklength Optimization in RIS-Aided Short Packet URLLC Systems," in IEEE Communications Letters, vol. 26, no. 8, pp. 1838-1842, Aug. 2022, doi: 10.1109/LCOMM.2022.3180396

Joint sum rate and blocklength optimization in RIS-aided short packet URLLC systems

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Author: Hashemi, Ramin1; Ali, Samad1; Mahmood, Nurul Huda1;
Organizations: 1Centre for Wireless Communications (CWC), University of Oulu, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2022-06-23


In this paper, a multi-objective optimization problem (MOOP) is proposed for maximizing the achievable finite blocklength (FBL) rate while minimizing the utilized channel blocklengths (CBLs) in a reconfigurable intelligent surface (RIS)-assisted short packet communication system. The formulated MOOP has two objective functions namely maximizing the total FBL rate with a target error probability, and minimizing the total utilized CBLs which is directly proportional to the transmission duration. The considered MOOP variables are the base station (BS) transmit power, number of CBLs, and passive beamforming at the RIS. Since the proposed non-convex problem is intractable to solve, the Tchebyshev method is invoked to transform it into a single-objective OP, then the alternating optimization (AO) technique is employed to iteratively obtain optimized parameters in three main sub-problems. The numerical results show a fundamental trade-off between maximizing the achievable rate in the FBL regime and reducing the transmission duration. Also, the applicability of RIS technology is emphasized in reducing the utilized CBLs while increasing the achievable rate significantly.

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Series: IEEE communications letters
ISSN: 1089-7798
ISSN-E: 2373-7891
ISSN-L: 1089-7798
Volume: 26
Issue: 8
DOI: 10.1109/lcomm.2022.3180396
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This research has been supported by the Academy of Finland, 6G Flagship program under Grant 346208.
Academy of Finland Grant Number: 346208
Detailed Information: 346208 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2022. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see