University of Oulu

M. Moltafet, M. Leinonen and M. Codreanu, "Moment Generating Function of the AoI in a Two-Source System With Packet Management," in IEEE Wireless Communications Letters, vol. 10, no. 4, pp. 882-886, April 2021, doi: 10.1109/LWC.2020.3048628

Moment generating function of the AoI in a two-source system with packet management

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Author: Moltafet, Mohammad1; Leinonen, Markus1; Codreanu, Marian2
Organizations: 1Centre for Wireless Communications–Radio Technologies, University of Oulu, 90014 Oulu, Finland
2Department of Science and Technology, Linköping University, 581 83 Linköping, Sweden
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, 2021
Publish Date: 2021-05-04


We consider a status update system consisting of two independent sources and one server in which packets of each source are generated according to the Poisson process and packets are served according to an exponentially distributed service time. We derive the moment generating function (MGF) of the age of information (AoI) for each source in the system by using the stochastic hybrid systems (SHS) under two existing source-aware packet management policies which we term self-preemptive and non-preemptive policies. In the both policies, the system (i.e., the waiting queue and the server) can contain at most two packets, one packet of each source; when the server is busy and a new packet arrives, the possible packet of the same source in the waiting queue is replaced by the fresh packet. The main difference between the policies is that in the self-preemptive policy, the packet under service is replaced upon the arrival of a new packet from the same source, whereas in the non-preemptive policy, this new arriving packet is blocked and cleared. We use the derived MGF to find the first and second moments of the AoI and show the importance of higher moments.

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Series: IEEE wireless communications letters
ISSN: 2162-2337
ISSN-E: 2162-2345
ISSN-L: 2162-2337
Volume: 10
Issue: 4
Pages: 882 - 886
Article number: 9312180
DOI: 10.1109/LWC.2020.3048628
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 Infotech Oulu; in part by the Academy of Finland under Grant 323698; and in part by the Academy of Finland 6Genesis Flagship under Grant 318927. The work of Mohammad Moltafet was supported in part by the Finnish Foundation for Technology Promotion, HPY Research Foundation; in part by Riitta ja Jorma J. Takanen Foundation; and in part by Nokia Foundation. The work of Markus Leinonen was supported in part by the Academy of Finland under Grant 319485. The work of Marian Codreanu was supported by the European Union’s Horizon 2020 Research and Innovation Programme through the Marie Skłodowska-Curie Grant Agreement 793402 (COMPRESS NETS).
Academy of Finland Grant Number: 323698
Detailed Information: 323698 (Academy of Finland Funding decision)
318927 (Academy of Finland Funding decision)
319485 (Academy of Finland Funding decision)
Copyright information: © The Authors 2021. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see