PMID- 36991727 OWN - NLM STAT- PubMed-not-MEDLINE DCOM- 20230330 LR - 20230401 IS - 1424-8220 (Electronic) IS - 1424-8220 (Linking) VI - 23 IP - 6 DP - 2023 Mar 10 TI - Machine Learning-Based Methods for Enhancement of UAV-NOMA and D2D Cooperative Networks. LID - 10.3390/s23063014 [doi] LID - 3014 AB - The cooperative aerial and device-to-device (D2D) networks employing non-orthogonal multiple access (NOMA) are expected to play an essential role in next-generation wireless networks. Moreover, machine learning (ML) techniques, such as artificial neural networks (ANN), can significantly enhance network performance and efficiency in fifth-generation (5G) wireless networks and beyond. This paper studies an ANN-based unmanned aerial vehicle (UAV) placement scheme to enhance an integrated UAV-D2D NOMA cooperative network.The proposed placement scheme selection (PSS) method for integrating the UAV into the cooperative network combines supervised and unsupervised ML techniques. Specifically, a supervised classification approach is employed utilizing a two-hidden layered ANN with 63 neurons evenly distributed among the layers. The output class of the ANN is utilized to determine the appropriate unsupervised learning method-either k-means or k-medoids-to be employed. This specific ANN layout has been observed to exhibit an accuracy of 94.12%, the highest accuracy among the ANN models evaluated, making it highly recommended for accurate PSS predictions in urban locations. Furthermore, the proposed cooperative scheme allows pairs of users to be simultaneously served through NOMA from the UAV, which acts as an aerial base station. At the same time, the D2D cooperative transmission for each NOMA pair is activated to improve the overall communication quality. Comparisons with conventional orthogonal multiple access (OMA) and alternative unsupervised machine-learning based-UAV-D2D NOMA cooperative networks show that significant sum rate and spectral efficiency gains can be harvested through the proposed method under varying D2D bandwidth allocations. FAU - Tsipi, Lefteris AU - Tsipi L AUID- ORCID: 0000-0002-2591-9289 AD - Department of Information and Communication Systems Engineering, School of Engineering, University of the Aegean, 83200 Samos, Greece. FAU - Karavolos, Michail AU - Karavolos M AUID- ORCID: 0000-0002-3707-3313 AD - Department of Information and Communication Systems Engineering, School of Engineering, University of the Aegean, 83200 Samos, Greece. FAU - Bithas, Petros S AU - Bithas PS AUID- ORCID: 0000-0002-6858-3674 AD - Department of Digital Industry Technologies, National and Kapodistrian University of Athens, Thesi Skliro, 34400 Evia, Greece. FAU - Vouyioukas, Demosthenes AU - Vouyioukas D AUID- ORCID: 0000-0002-6649-6577 AD - Department of Information and Communication Systems Engineering, School of Engineering, University of the Aegean, 83200 Samos, Greece. LA - eng PT - Journal Article DEP - 20230310 PL - Switzerland TA - Sensors (Basel) JT - Sensors (Basel, Switzerland) JID - 101204366 SB - IM PMC - PMC10055871 OTO - NOTNLM OT - D2D OT - NOMA OT - UAV placement OT - artificial neural network (ANN) OT - cooperative communications OT - deep neural network (DNN) OT - machine learning COIS- The authors declare no conflict of interest. EDAT- 2023/03/31 06:00 MHDA- 2023/03/31 06:01 PMCR- 2023/03/10 CRDT- 2023/03/30 01:02 PHST- 2022/12/20 00:00 [received] PHST- 2023/03/06 00:00 [revised] PHST- 2023/03/07 00:00 [accepted] PHST- 2023/03/31 06:01 [medline] PHST- 2023/03/30 01:02 [entrez] PHST- 2023/03/31 06:00 [pubmed] PHST- 2023/03/10 00:00 [pmc-release] AID - s23063014 [pii] AID - sensors-23-03014 [pii] AID - 10.3390/s23063014 [doi] PST - epublish SO - Sensors (Basel). 2023 Mar 10;23(6):3014. doi: 10.3390/s23063014.