{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,18]],"date-time":"2026-04-18T03:06:02Z","timestamp":1776481562646,"version":"3.51.2"},"reference-count":55,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2023,7,29]],"date-time":"2023-07-29T00:00:00Z","timestamp":1690588800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Deanship of Scientific Research at Najran University","award":["NU\/RG\/SERC\/12\/9"],"award-info":[{"award-number":["NU\/RG\/SERC\/12\/9"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The diverse application vertices of internet-of-things (IoT) including internet of vehicles (IoV), industrial IoT (IIoT) and internet of drones things (IoDT) involve intelligent communication between the massive number of objects around us. This digital transformation strives for seamless data flow, uninterrupted communication capabilities, low latency and ultra-high reliability. The limited capabilities of fifth generation (5G) technology have given way to sixth generation (6G) wireless technology. This paper presents a dynamic cell-free framework for a 6G-enabled IoT network. A number of access points (APs) are distributed over a given geographical area to serve a large number of user nodes. A pilot-based AP selection (PBAS) algorithm is proposed, which offers robust resource control through AP selection based on pilots. Selecting a subset of APs against all APs for each user node results in improved performance. In this paper, the performance of the proposed transmission model is evaluated for the achieved data rate and spectral efficiency using the proposed algorithm. It is shown that the proposed PBAS algorithm improves the spectral efficiency by 22% at the cell-edge and 1.5% at the cell-center. A comparison of the different combining techniques used at different user locations is also provided, along with the mathematical formulations. Finally, the proposed model is compared with two other transmission models for performance evaluation. It is observed that the spectral efficiency achieved by an edge node with the proposed scheme is 5.3676 bits\/s\/Hz, compared to 0.756 bits\/s\/Hz and 1.0501 bits\/s\/Hz, attained with transmission schemes 1 and 2, respectively.<\/jats:p>","DOI":"10.3390\/s23156788","type":"journal-article","created":{"date-parts":[[2023,7,31]],"date-time":"2023-07-31T03:30:02Z","timestamp":1690774202000},"page":"6788","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Robust Resource Control Based on AP Selection in 6G-Enabled IoT Networks"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6468-3686","authenticated-orcid":false,"given":"Ashu","family":"Taneja","sequence":"first","affiliation":[{"name":"Chitkara University Institute of Engineering and Technology, Chitkara University, Rajpura 140401, Punjab, India"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7111-8810","authenticated-orcid":false,"given":"Ali","family":"Alqahtani","sequence":"additional","affiliation":[{"name":"Department of Networks and Communications Engineering, College of Computer Science and Information Systems, Najran University, Najran 61441, Najran, Saudi Arabia"}]},{"given":"Nitin","family":"Saluja","sequence":"additional","affiliation":[{"name":"Chitkara University Institute of Engineering and Technology, Chitkara University, Rajpura 140401, Punjab, India"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7481-8396","authenticated-orcid":false,"given":"Nayef","family":"Alqahtani","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, College of Engineering, King Faisal University, Al-Hofuf 31982, Al-Ahsa, Saudi Arabia"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4246","DOI":"10.1109\/TVT.2020.2970553","article-title":"Accessibility Analysis and Modeling for IoV in an Urban Scene","volume":"69","author":"Cheng","year":"2020","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"8707","DOI":"10.1109\/JIOT.2020.3045653","article-title":"Recent Advances in the Internet-of-Medical-Things (IoMT) Systems Security","volume":"8","author":"Ghubaish","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"968","DOI":"10.1109\/ACCESS.2021.3134264","article-title":"Reliable Data Transmission Scheme for Perception Layer of Internet of Underwater Things (IoUT)","volume":"10","author":"Ishaque","year":"2022","journal-title":"IEEE Access"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6406","DOI":"10.1109\/JIOT.2020.3015382","article-title":"Enabling Drones in the Internet of Things with Decentralized Blockchain-Based Security","volume":"8","author":"Yazdinejad","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1109\/OJCOMS.2022.3143098","article-title":"Towards 6G-Enabled Internet of Vehicles: Security and Privacy","volume":"3","author":"Ahmad","year":"2022","journal-title":"IEEE Open J. Commun. Soc."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Nekovee, M. (2022, January 4\u20138). Transformation from 5G for Verticals towards a 6G-enabled Internet of Verticals. Proceedings of the 2022 14th International Conference on COMmunication Systems NETworkS (COMSNETS), Bangalore, India.","DOI":"10.1109\/COMSNETS53615.2022.9668541"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1109\/COMST.2022.3151028","article-title":"Cellular, Wide-Area, and Non-Terrestrial IoT: A Survey on 5G Advances and the Road towards 6G","volume":"24","author":"Vaezi","year":"2022","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1637","DOI":"10.1109\/JSAC.2020.3000826","article-title":"Prospective Multiple Antenna Technologies for beyond 5G","volume":"38","author":"Zhang","year":"2020","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1140","DOI":"10.1109\/TCOMM.2021.3136563","article-title":"IRS-Assisted Secure UAV Transmission via Joint Trajectory and Beamforming Design","volume":"70","author":"Pang","year":"2022","journal-title":"IEEE Trans. Commun."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"116106","DOI":"10.1016\/j.eswa.2021.116106","article-title":"An optimized scheme for energy efficient wireless communication via intelligent reflecting surfaces","volume":"190","author":"Taneja","year":"2022","journal-title":"Expert Syst. Appl."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3103","DOI":"10.1109\/TCOMM.2023.3255900","article-title":"Channel Modeling for UAV-to-Ground Communications With Posture Variation and Fuselage Scattering Effect","volume":"71","author":"Hua","year":"2023","journal-title":"IEEE Trans. Commun."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3951","DOI":"10.1109\/TCSI.2021.3087777","article-title":"A Real-Time Hardware Emulator for 3D Non-Stationary U2V Channels","volume":"68","author":"Zhu","year":"2021","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"854","DOI":"10.1109\/JSAC.2019.2898756","article-title":"The Impact of Mobile Blockers on Millimeter Wave Cellular Systems","volume":"37","author":"Jain","year":"2019","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1109\/MCOM.2018.1600731","article-title":"On Low-Resolution ADCs in Practical 5G Millimeter-Wave Massive MIMO Systems","volume":"56","author":"Zhang","year":"2018","journal-title":"IEEE Commun. Mag."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1109\/TVT.2018.2880788","article-title":"Coordinated Multi-Point Downlink Transmission for Dense Small Cell Networks","volume":"68","author":"Liao","year":"2019","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7996","DOI":"10.1109\/TWC.2017.2756044","article-title":"Heterogeneous Cellular Networks with LoS and NLoS Transmissions\u2014The Role of Massive MIMO and Small Cells","volume":"16","author":"Zhang","year":"2017","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1561\/2000000093","article-title":"Massive MIMO networks: Spectral, energy, and hardware efficiency","volume":"11","author":"Hoydis","year":"2017","journal-title":"Found. Trends\u00ae Signal Process."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.dsp.2019.06.007","article-title":"Massive MIMO is a reality\u2014What is next?: Five promising research directions for antenna arrays","volume":"94","author":"Sanguinetti","year":"2019","journal-title":"Digit. Signal Process."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1109\/TCOMM.2019.2945792","article-title":"Toward Massive MIMO 2.0: Understanding Spatial Correlation, Interference Suppression, and Pilot Contamination","volume":"68","author":"Sanguinetti","year":"2020","journal-title":"IEEE Trans. Commun."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"99878","DOI":"10.1109\/ACCESS.2019.2930208","article-title":"Cell-Free Massive MIMO: A New Next-Generation Paradigm","volume":"7","author":"Zhang","year":"2019","journal-title":"IEEE Access"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1250","DOI":"10.1109\/TWC.2019.2952117","article-title":"User-Centric 5G Cellular Networks: Resource Allocation and Comparison with the Cell-Free Massive MIMO Approach","volume":"19","author":"Buzzi","year":"2020","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1109\/COMST.2021.3135119","article-title":"User-Centric Cell-Free Massive MIMO Networks: A Survey of Opportunities, Challenges and Solutions","volume":"24","author":"Ammar","year":"2022","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1002\/bltj.21603","article-title":"Network-centric cooperation schemes for uplink interference management in cellular networks","volume":"18","author":"Balachandran","year":"2013","journal-title":"Bell Labs Tech. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"7252","DOI":"10.1109\/JIOT.2020.3039236","article-title":"Energy-Efficient Operation of Massive MIMO in Industrial Internet-of-Things Networks","volume":"8","author":"Lee","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4669","DOI":"10.1109\/TII.2020.3019049","article-title":"Massive MIMO with Downlink Energy Efficiency Operation in Industrial Internet of Things","volume":"17","author":"Lee","year":"2021","journal-title":"IEEE Trans. Ind. Inform."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5187","DOI":"10.1109\/TIE.2019.2924855","article-title":"Massive MIMO with Massive Connectivity for Industrial Internet of Things","volume":"67","author":"Lee","year":"2020","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2585","DOI":"10.1109\/JIOT.2020.3019029","article-title":"Adaptive Switching Scheme for RS Overhead Reduction in Massive MIMO with Industrial Internet of Things","volume":"8","author":"Lee","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2282","DOI":"10.1109\/COMST.2016.2548658","article-title":"Recent Advances in Cloud Radio Access Networks: System Architectures, Key Techniques, and Open Issues","volume":"18","author":"Peng","year":"2016","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1834","DOI":"10.1109\/TWC.2017.2655515","article-title":"Cell-Free Massive MIMO Versus Small Cells","volume":"16","author":"Ngo","year":"2017","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4803","DOI":"10.1109\/TCOMM.2020.2990951","article-title":"Downlink Spectral Efficiency of Cell-Free Massive MIMO Systems With Multi-Antenna Users","volume":"68","author":"Mai","year":"2020","journal-title":"IEEE Trans. Commun."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Burr, A., Islam, S., Zhao, J., and Bashar, M. (2020, January 1\u20135). Cell-free Massive MIMO with multi-antenna access points and user terminals. Proceedings of the 2020 54th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA.","DOI":"10.1109\/IEEECONF51394.2020.9443558"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Mai, T.C., Quoc Ngo, H., and Duong, T.Q. (2018, January 26\u201328). CELL-FREE MASSIVE MIMO SYSTEMS WITH MULTI-ANTENNA USERS. Proceedings of the 2018 IEEE Global Conference on Signal and Information Processing (GlobalSIP), Anaheim, CA, USA.","DOI":"10.1109\/GlobalSIP.2018.8646330"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"92","DOI":"10.23919\/JCC.2020.12.007","article-title":"Wireless powered IoE for 6G: Massive access meets scalable cell-free massive MIMO","volume":"17","author":"Chen","year":"2020","journal-title":"China Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"13780","DOI":"10.1109\/JIOT.2022.3143531","article-title":"Cell-Free IoT Networks with SWIPT: Performance Analysis and Power Control","volume":"9","author":"Zhang","year":"2022","journal-title":"IEEE Internet Things J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"616","DOI":"10.1109\/LWC.2018.2890470","article-title":"Modified Conjugate Beamforming for Cell-Free Massive MIMO","volume":"8","author":"Attarifar","year":"2019","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Yang, H., and Marzetta, T.L. (2018, January 3\u20136). Energy Efficiency of Massive MIMO: Cell-Free vs. Cellular. Proceedings of the 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), Porto, Portugal.","DOI":"10.1109\/VTCSpring.2018.8417645"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1109\/TGCN.2017.2770215","article-title":"On the Total Energy Efficiency of Cell-Free Massive MIMO","volume":"2","author":"Ngo","year":"2018","journal-title":"IEEE Trans. Green Commun. Netw."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"634","DOI":"10.1109\/LWC.2020.3044301","article-title":"Grant-Free Massive Connectivity in Massive MIMO Systems: Collocated Versus Cell-Free","volume":"10","author":"Wang","year":"2021","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"146","DOI":"10.23919\/JCC.2021.06.012","article-title":"Spectral efficiency of superimposed pilots in cell-free massive MIMO systems with hardware impairments","volume":"18","author":"Zhang","year":"2021","journal-title":"China Commun."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"9701","DOI":"10.1109\/TVT.2021.3109341","article-title":"Scalable Cell-Free Massive MIMO Systems: Impact of Hardware Impairments","volume":"70","author":"Papazafeiropoulos","year":"2021","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Nayebi, E., Ashikhmin, A., Marzetta, T.L., and Rao, B.D. (2016, January 6\u20139). Performance of cell-free massive MIMO systems with MMSE and LSFD receivers. Proceedings of the 2016 50th Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA.","DOI":"10.1109\/ACSSC.2016.7869024"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Bj\u00f6rnson, E., and Sanguinetti, L. (2019, January 8\u201311). A New Look at Cell-Free Massive MIMO: Making It Practical With Dynamic Cooperation. Proceedings of the 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Istanbul, Turkey.","DOI":"10.1109\/PIMRC.2019.8904101"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1109\/TWC.2019.2941478","article-title":"Making Cell-Free Massive MIMO Competitive with MMSE Processing and Centralized Implementation","volume":"19","author":"Sanguinetti","year":"2020","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"4758","DOI":"10.1109\/TWC.2020.2987027","article-title":"Local Partial Zero-Forcing Precoding for Cell-Free Massive MIMO","volume":"19","author":"Interdonato","year":"2020","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"4445","DOI":"10.1109\/TWC.2017.2698449","article-title":"Precoding and Power Optimization in Cell-Free Massive MIMO Systems","volume":"16","author":"Nayebi","year":"2017","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Ngo, H.Q., Tataria, H., Matthaiou, M., Jin, S., and Larsson, E.G. (2018, January 28\u201331). On the Performance of Cell-Free Massive MIMO in Ricean Fading. Proceedings of the 2018 52nd Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA.","DOI":"10.1109\/ACSSC.2018.8645336"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"5299","DOI":"10.1109\/TWC.2019.2935434","article-title":"Performance of Cell-Free Massive MIMO With Rician Fading and Phase Shifts","volume":"18","author":"Ozdogan","year":"2019","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Fan, W., Zhang, J., Bjornson, E., Chen, S., and Zhong, Z. (2019, January 20\u201324). Performance Analysis of Cell-Free Massive MIMO Over Spatially Correlated Fading Channels. Proceedings of the ICC 2019\u20142019 IEEE International Conference on Communications (ICC), Shanghai, China.","DOI":"10.1109\/ICC.2019.8762051"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"7520","DOI":"10.1109\/TCOMM.2021.3102635","article-title":"Clustering-Based Activity Detection Algorithms for Grant-Free Random Access in Cell-Free Massive MIMO","volume":"69","author":"Ganesan","year":"2021","journal-title":"IEEE Trans. Commun."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"14705","DOI":"10.1109\/JIOT.2021.3071781","article-title":"A Scalable and Energy-Efficient IoT System Supported by Cell-Free Massive MIMO","volume":"8","author":"Yan","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2709","DOI":"10.1109\/TCOMM.2020.3047801","article-title":"Joint Power Control and Access Point Scheduling in Fronthaul-Constrained Uplink Cell-Free Massive MIMO Systems","volume":"69","author":"Guenach","year":"2021","journal-title":"IEEE Trans. Commun."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"102770","DOI":"10.1109\/ACCESS.2021.3098638","article-title":"Uplink Signal Detection for Scalable Cell-Free Massive MIMO Systems with Robustness to Rate-Limited Fronthaul","volume":"9","author":"Ando","year":"2021","journal-title":"IEEE Access"},{"key":"ref_53","unstructured":"3GPP (2023, May 20). Further Advancements for E-UTRA Physical Layer Aspects (Release 9). Available online: https:\/\/portal.3gpp.org\/desktopmodules\/Specifications\/SpecificationDetails.aspx?specificationId=2493."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Jung, S., Hong, S.E., and Na, J.H. (2022, January 19\u201321). Access Point Selection Schemes for Cell-free Massive MIMO UDN Systems. Proceedings of the 2022 13th International Conference on Information and Communication Technology Convergence (ICTC), Jeju Island, Republic of Korea.","DOI":"10.1109\/ICTC55196.2022.9952923"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"108127","DOI":"10.1109\/ACCESS.2020.3001270","article-title":"Effective Channel Gain-Based Access Point Selection in Cell-Free Massive MIMO Systems","volume":"8","author":"Dao","year":"2020","journal-title":"IEEE Access"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/15\/6788\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:22:13Z","timestamp":1760127733000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/15\/6788"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,29]]},"references-count":55,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2023,8]]}},"alternative-id":["s23156788"],"URL":"https:\/\/doi.org\/10.3390\/s23156788","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,29]]}}}