PMID- 35336350
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20220328
IS  - 1424-8220 (Electronic)
IS  - 1424-8220 (Linking)
VI  - 22
IP  - 6
DP  - 2022 Mar 10
TI  - Two-Stage Multiarmed Bandit for Reconfigurable Intelligent Surface Aided 
      Millimeter Wave Communications.
LID - 10.3390/s22062179 [doi]
LID - 2179
AB  - A reconfigurable intelligent surface (RIS) is a promising technology that can 
      extend short-range millimeter wave (mmWave) communications coverage. However, 
      phase shifts (PSs) of both mmWave transmitter (TX) and RIS antenna elements need 
      to be optimally adjusted to effectively cover a mmWave user. This paper proposes 
      codebook-based phase shifters for mmWave TX and RIS to overcome the difficulty of 
      estimating their mmWave channel state information (CSI). Moreover, to adjust the 
      PSs of both, an online learning approach in the form of a multiarmed bandit (MAB) 
      game is suggested, where a nested two-stage stochastic MAB strategy is proposed. 
      In the proposed strategy, the PS vector of the mmWave TX is adjusted in the first 
      MAB stage. Based on it, the PS vector of the RIS is calibrated in the second 
      stage and vice versa over the time horizon. Hence, we leverage and implement two 
      standard MAB algorithms, namely Thompson sampling (TS) and upper confidence bound 
      (UCB). Simulation results confirm the superior performance of the proposed nested 
      two-stage MAB strategy; in particular, the nested two-stage TS nearly matches the 
      optimal performance.
FAU - Mohamed, Ehab Mahmoud
AU  - Mohamed EM
AUID- ORCID: 0000-0001-5443-9711
AD  - Electrical Engineering Department, College of Engineering at Wadi Addwasir, 
      Prince Sattam Bin Abdulaziz University, Wadi Addwasir 11991, Saudi Arabia.
AD  - Electrical Engineering Department, Faculty of Engineering, Aswan University, 
      Aswan 81542, Egypt.
FAU - Hashima, Sherief
AU  - Hashima S
AUID- ORCID: 0000-0002-4443-7066
AD  - Computational Learning Theory Team, RIKEN-Advanced Intelligent Project, Fukuoka 
      819-0395, Japan.
AD  - Engineering and Scientific Equipment's Department, Egyptian Atomic Energy 
      Authority, Cairo 13759, Egypt.
FAU - Hatano, Kohei
AU  - Hatano K
AUID- ORCID: 0000-0002-1536-1269
AD  - Computational Learning Theory Team, RIKEN-Advanced Intelligent Project, Fukuoka 
      819-0395, Japan.
AD  - Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan.
FAU - Aldossari, Saud Alhajaj
AU  - Aldossari SA
AUID- ORCID: 0000-0001-7219-7744
AD  - Electrical Engineering Department, College of Engineering at Wadi Addwasir, 
      Prince Sattam Bin Abdulaziz University, Wadi Addwasir 11991, Saudi Arabia.
LA  - eng
GR  - (IF-PSAU-2021/01/18041)/Deputyship for Research & Innovation, Ministry of 
      Education in Saudi Arabia for funding this research work through the project 
      number (IF-PSAU-2021/01/18041)/
PT  - Journal Article
DEP - 20220310
PL  - Switzerland
TA  - Sensors (Basel)
JT  - Sensors (Basel, Switzerland)
JID - 101204366
SB  - IM
PMC - PMC8953326
OTO - NOTNLM
OT  - Thompson sampling
OT  - millimeter wave
OT  - multiarmed bandit
OT  - reconfigurable intelligent surface
OT  - upper confidence bound
COIS- The authors declare no conflict of interest.
EDAT- 2022/03/27 06:00
MHDA- 2022/03/27 06:01
PMCR- 2022/03/10
CRDT- 2022/03/26 01:05
PHST- 2021/12/04 00:00 [received]
PHST- 2022/02/22 00:00 [revised]
PHST- 2022/03/04 00:00 [accepted]
PHST- 2022/03/26 01:05 [entrez]
PHST- 2022/03/27 06:00 [pubmed]
PHST- 2022/03/27 06:01 [medline]
PHST- 2022/03/10 00:00 [pmc-release]
AID - s22062179 [pii]
AID - sensors-22-02179 [pii]
AID - 10.3390/s22062179 [doi]
PST - epublish
SO  - Sensors (Basel). 2022 Mar 10;22(6):2179. doi: 10.3390/s22062179.