Two-Stage Thompson Sampling for Outer-Loop Link Adaptation

Jeonghun Park, Seungkwon Baek

Research output: Contribution to journalArticlepeer-review


In this letter, we consider outer-loop link adaptation, wherein we pursue to find the optimum modulation and coding scheme (MCS) that provides the maximum throughput without directly estimating the channel state. We cast this problem in a form of multi-armed bandit, an online decision making policy based on sequential observations. To efficiently solve a formulated problem, we propose a novel two-stage Thompson sampling. The proposed method is built based on the observation that the optimum MCS level appears in a certain group that satisfies feasibility conditions. Exploiting this feature, we find the optimum MCS level via two stages. In the first stage, we identify a group that has high probability of including the optimum MCS. In the second stage, we only focus on the MCS levels within the identified group in the first stage, and investigate the optimum MCS. By doing this, the search space is significantly reduced, which leads to the performance improvement. Simulation results show that the proposed method outperforms the existing state-of-art algorithm.

Original languageEnglish
Article number9459019
Pages (from-to)2004-2008
Number of pages5
JournalIEEE Wireless Communications Letters
Issue number9
Publication statusPublished - 2021 Sept

Bibliographical note

Funding Information:
Manuscript received May 23, 2021; accepted June 9, 2021. Date of publication June 17, 2021; date of current version September 9, 2021. This work was supported in part by the Institute of Information and Communications Technology Planning and Evaluation (IITP) Grant funded by the Korea Government (MSIT, Collaborative research on beyond 5G radio communication technology for ultra high speed media service in High Speed Train) under Grant 20190-01460. The associate editor coordinating the review of this article and approving it for publication was H. Yomo. (Corresponding author: Jeonghun Park.) Jeonghun Park is with the School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, South Korea (e-mail:

Publisher Copyright:
© 2012 IEEE.

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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