Comprehensive Throughput Analysis of Unslotted ALOHA for Low-Power Wide-Area Networks

Jun Bae Seo, Yangqian Hu, Sangheon Pack, Hu Jin

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Unslotted ALOHA has been often employed by several low-power wide-area networks (LPWANs) for Internet of Things (IoT) as a random access (RA) protocol. This work analyzes the performance of unslotted ALOHA systems in terms of throughput and RA delay, and investigates their optimization. Our analysis consists of: 1) two-heterogeneous user case, whose backoff rate and packet length are different; 2) N -homogeneous user case, whose backoff rate and packet length are identical; and 3) homogeneous users of infinite population model. In the two-user case, we investigate the throughput region of unslotted ALOHA by using a multiobjective optimization problem (MOOP) and derive the Laplace Stieltjes transform (LST) of the probability density function (PDF) of RA delay. For N -homogeneous user case, we show how the throughput behaves according to the population size, packet length, and backoff rate. Our work may provide a comprehensive analytical framework for unslotted ALOHA systems.

Original languageEnglish
Pages (from-to)15800-15813
Number of pages14
JournalIEEE Internet of Things Journal
Issue number17
Publication statusPublished - 2022 Sept 1

Bibliographical note

Funding Information:
This work was supported in part by the National Research Foundation of Korea (NRF) Grant funded by the Korea Government (MSIT) under Grant NRF-2021R1F1A1063057; in part by the Ministry of Science and ICT (MSIT), South Korea, under the Information Technology Research Center (ITRC) Support Program under Grant IITP-2021-2017-0- 01633 Supervised by the Institute for Information and Communications Technology Planning and Evaluation (IITP); and in part by the "5G-Based IoT Core Technology Development Project" Grant funded by the Korea Government (MSIT, Core Technologies for Enhancing Wireless Connectivity of Unlicensed Band Massive IoT in 5G+ Smart City Environment) under Grant 2020-0-00167.

Publisher Copyright:
© 2022 IEEE.


  • Access delay
  • heterogeneous users
  • pure ALOHA
  • renewal theorem throughput
  • unslotted ALOHA

ASJC Scopus subject areas

  • Signal Processing
  • Information Systems
  • Hardware and Architecture
  • Computer Science Applications
  • Computer Networks and Communications


Dive into the research topics of 'Comprehensive Throughput Analysis of Unslotted ALOHA for Low-Power Wide-Area Networks'. Together they form a unique fingerprint.

Cite this