{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T03:23:31Z","timestamp":1774668211331,"version":"3.50.1"},"reference-count":51,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2022,12,1]],"date-time":"2022-12-01T00:00:00Z","timestamp":1669852800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"CHIST-ERA","award":["CHIST-ERA-20-SICT-003"],"award-info":[{"award-number":["CHIST-ERA-20-SICT-003"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Currently, 5G and the forthcoming 6G mobile communication systems are the most promising cellular generations expected to beat the growing hunger for bandwidth and enable the fully connected world presented by the Internet of Everything (IoE). The cloud radio access network (CRAN) has been proposed as a promising architecture for meeting the needs and goals of 5G\/6G (5G and beyond) networks. Nevertheless, the provisioning of cost-efficient connections between a large number of remote radio heads (RRHs) in the cell sites and the baseband unit (BBU) pool in the central location, known as the fronthaul, has emerged as a new challenge. Many wired and wireless solutions have been proposed to address this bottleneck. Specifically, optical technologies presented by passive optical networks (PONs) are introduced as the best suitable solution for 5G and beyond network fronthaul due to their properties of providing high capacity and low latency connections. We considered time and wavelength division multiplexed passive optical networks (TWDM-PONs) as a fronthaul for 5G and beyond. Taking that into consideration, in this paper, we propose an integer linear program (ILP) that results in the optimal optical fronthaul deployment while minimizing the total cost of 5G and beyond instances. However, for larger network instances, solving the ILP problem becomes unscalable and time-consuming. To address that, we developed two heuristic-based algorithms (the K-means clustering algorithm and the one based on the genetic algorithm\u2014GA). We evaluated the suitability of our proposed ILP and heuristic algorithms in simulations by utilizing them to plan different network instances (dense and sparse).<\/jats:p>","DOI":"10.3390\/s22239394","type":"journal-article","created":{"date-parts":[[2022,12,2]],"date-time":"2022-12-02T03:28:04Z","timestamp":1669951684000},"page":"9394","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":43,"title":["Design of Cost-Efficient Optical Fronthaul for 5G\/6G Networks: An Optimization Perspective"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4933-766X","authenticated-orcid":false,"given":"Abdulhalim","family":"Fayad","sequence":"first","affiliation":[{"name":"Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics (BME), 1117 Budapest, Hungary"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3605-445X","authenticated-orcid":false,"given":"Tibor","family":"Cinkler","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics (BME), 1117 Budapest, Hungary"},{"name":"Faculty of Electronics, Telecommunications and Informatics, Gda\u0144sk University of Technology, G. Narutowicza 11\/12, 80-233 Gda\u0144sk, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7276-6097","authenticated-orcid":false,"given":"Jacek","family":"Rak","sequence":"additional","affiliation":[{"name":"Faculty of Electronics, Telecommunications and Informatics, Gda\u0144sk University of Technology, G. Narutowicza 11\/12, 80-233 Gda\u0144sk, Poland"}]},{"given":"Manish","family":"Jha","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics (BME), 1117 Budapest, Hungary"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,1]]},"reference":[{"key":"ref_1","unstructured":"ITU-R (2022, October 11). IMT Traffic Estimates for the Years 2020 to 2030. ITU. Available online: www.itu.int\/pub\/R-REP-M.2370-2015."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1617","DOI":"10.1109\/COMST.2016.2532458","article-title":"Next generation 5G wireless networks: A comprehensive survey","volume":"18","author":"Agiwal","year":"2016","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1109\/OJCOMS.2021.3057679","article-title":"The road towards 6G: A comprehensive survey","volume":"2","author":"Jiang","year":"2021","journal-title":"IEEE Open J. Commun. Soc."},{"key":"ref_4","unstructured":"Khan, W.U., Mahmood, A., Bozorgchenani, A., Jamshed, M.A., Ranjha, A., Lagunas, E., Pervaiz, H., Chatzinotas, S., Ottersten, B., and Popovski, P. (2022). Opportunities for Intelligent Reflecting Surfaces in 6G-Empowered V2X Communications. arXiv."},{"key":"ref_5","first-page":"2419","article-title":"Vision and research directions of 6G technologies and applications","volume":"34","author":"Hakeem","year":"2022","journal-title":"J. King Saud Univ.-Comput. Inf. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Khan, W.U., Javed, M.A., Zeadally, S., Lagunas, E., and Chatzinotas, S. (2022). Intelligent and Secure Radio Environments for 6G Vehicular Aided HetNets: Key Opportunities and Challenges. arXiv.","DOI":"10.1109\/MCOMSTD.0007.2200065"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1109\/COMST.2017.2773462","article-title":"Toward an efficient C-RAN optical fronthaul for the future networks: A tutorial on technologies, requirements, challenges, and solutions","volume":"20","author":"Alimi","year":"2017","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1007\/s11107-019-00856-w","article-title":"A survey on role of photonic technologies in 5G communication systems","volume":"38","author":"Katti","year":"2019","journal-title":"Photonic Netw. Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4639","DOI":"10.1109\/TNSM.2021.3094789","article-title":"Optimized Joint Allocation of Radio, Optical, and MEC Resources for the 5G and Beyond Fronthaul","volume":"18","author":"Lagkas","year":"2021","journal-title":"IEEE Trans. Netw. Serv. Manag."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1109\/MWC.2014.7000980","article-title":"Heterogeneous cloud radio access networks: A new perspective for enhancing spectral and energy efficiencies","volume":"21","author":"Peng","year":"2014","journal-title":"IEEE Wirel. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1109\/MNET.2016.7513863","article-title":"Fog-computing-based radio access networks: Issues and challenges","volume":"30","author":"Peng","year":"2016","journal-title":"IEEE Netw."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Singh, S.K., Singh, R., and Kumbhani, B. (2020, January 6\u20139). The evolution of radio access network towards open-RAN: Challenges and opportunities. Proceedings of the 2020 IEEE Wireless Communications and Networking Conference Workshops (WCNCW), Seoul, Republic of Korea.","DOI":"10.1109\/WCNCW48565.2020.9124820"},{"key":"ref_13","unstructured":"(2022, October 04). Transport Network Support of IMT-2020\/5G\u2014ITU Hub. ITU Hub. Available online: www.itu.int\/hub\/publication\/t-tut-home-2018."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Wang, X., Cavdar, C., Wang, L., Tornatore, M., Zhao, Y., Chung, H.S., Lee, H.H., Park, S., and Mukherjee, B. (2016, January 4\u20138). Joint allocation of radio and optical resources in virtualized cloud RAN with CoMP. Proceedings of the 2016 IEEE Global Communications Conference (GLOBECOM), Washington, DC, USA.","DOI":"10.1109\/GLOCOM.2016.7841923"},{"key":"ref_15","unstructured":"(2022, October 06). 3GPP TR 38.801. Study on New Radio Access Technology: Radio Access Architecture and Interfaces. StandICT.eu. Available online: 2020.standict.eu\/standards-watch\/study-new-radio-access-technology-radio-access-architecture-and-interfaces."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Gomes, N.J., and Assimakopoulos, P. (2018, January 1\u20135). Optical fronthaul options for meeting 5G requirements. Proceedings of the 2018 20th International Conference on Transparent Optical Networks (ICTON), Bucharest, Romania.","DOI":"10.1109\/ICTON.2018.8473762"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1109\/COMST.2018.2868805","article-title":"A survey of the functional splits proposed for 5G mobile crosshaul networks","volume":"21","author":"Larsen","year":"2018","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"D10","DOI":"10.1364\/JOCN.9.000D10","article-title":"Optical transport solutions for 5G fixed wireless access","volume":"9","author":"Skubic","year":"2017","journal-title":"J. Opt. Commun. Netw."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3893","DOI":"10.1109\/JLT.2019.2921378","article-title":"Optical transport network design for 5G fixed wireless access","volume":"37","author":"Ranaweera","year":"2019","journal-title":"J. Light. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1109\/JPROC.2020.2976703","article-title":"A key 6G challenge and opportunity\u2014Connecting the base of the pyramid: A survey on rural connectivity","volume":"108","author":"Yaacoub","year":"2020","journal-title":"Proc. IEEE"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1007\/s11107-019-00842-2","article-title":"Resilience\u2013throughput\u2013power trade-off in future 5G photonic networks","volume":"37","author":"Cinkler","year":"2019","journal-title":"Photonic Netw. Commun."},{"key":"ref_22","first-page":"231","article-title":"Time and Wavelength Division Multiplexing Passive Optical Network comparative analysis: Modulation formats and channel spacings","volume":"15","author":"Fayad","year":"2021","journal-title":"Int. J. Electron. Commun. Eng."},{"key":"ref_23","unstructured":"(2022, November 26). ITU-T G.989.3: 40-Gigabit-Capable Passive Optical Networks (NG-PON2): Transmission Convergence Layer Specification. Available online: www.itu.int\/rec\/T-REC-G.989.3-202105-I\/en."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"7642","DOI":"10.1109\/TCOMM.2019.2939319","article-title":"Wavelength and bandwidth allocation for mobile fronthaul in TWDM-PON","volume":"67","author":"Nakayama","year":"2019","journal-title":"IEEE Trans. Commun."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Fayad, A., Jha, M., Cinkler, T., and Rak, J. (2022, January 16\u201319). Planning a Cost-Effective Delay-Constrained Passive Optical Network for 5G Fronthaul. Proceedings of the 2022 International Conference on Optical Network Design and Modeling (ONDM), Warsaw, Poland.","DOI":"10.23919\/ONDM54585.2022.9782857"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1007\/s11107-010-0297-4","article-title":"Geography-and infrastructure-aware topology design methodology for broadband access networks (FTTx)","volume":"21","author":"Mitcsenkov","year":"2011","journal-title":"Photonic Netw. Commun."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"102500","DOI":"10.1016\/j.yofte.2021.102500","article-title":"A low cost PON-FSO based fronthaul solution for 5G CRAN architecture","volume":"63","author":"Jaffer","year":"2021","journal-title":"Opt. Fiber Technol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"123541","DOI":"10.1109\/ACCESS.2021.3107243","article-title":"Enhancing Resilience of FSO Networks to Adverse Weather Conditions","volume":"9","author":"Kalesnikau","year":"2021","journal-title":"IEEE Access"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"19","DOI":"10.36244\/ICJ.2022.2.2","article-title":"Cost-Effective Delay-Constrained Optical Fronthaul Design for 5G and Beyond","volume":"14","author":"Fayad","year":"2022","journal-title":"Infocommun. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"8733","DOI":"10.1109\/ACCESS.2021.3049636","article-title":"Cost Analysis of 5G Fronthaul Networks Through Functional Splits at the PHY Layer in a Capacity and Cost Limited Scenario","volume":"9","author":"Rony","year":"2021","journal-title":"IEEE Access"},{"key":"ref_31","unstructured":"TEAM, ETSI COMS (2022, November 11). \u201cETSI\u2014ETSI Publishes Report on 5G Wireless Backhaul\/X-Haul.\u201d ETSI\u2014ETSI Publishes. Report on 5G Wireless Backhaul\/X-Haul. Available online: www.etsi.org\/committee?id=1465."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Hilt, A. (2019, January 1\u20133). Microwave hop-length and availability targets for the 5G mobile backhaul. Proceedings of the 2019 42nd International Conference on Telecommunications and Signal Processing (TSP), Budapest, Hungary.","DOI":"10.1109\/TSP.2019.8768870"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1963","DOI":"10.1109\/JLT.2015.2513101","article-title":"Optimal BBU placement for 5G C-RAN deployment over WDM aggregation networks","volume":"34","author":"Musumeci","year":"2016","journal-title":"J. Light. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"B1","DOI":"10.1364\/JOCN.8.0000B1","article-title":"Cost-minimized design for TWDM-PON-based 5G mobile backhaul networks","volume":"8","author":"Chen","year":"2016","journal-title":"J. Opt. Commun. Netw."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Klinkowski, M. (2018, January 1\u20135). Planning of 5G C-RAN with optical fronthaul: A scalability analysis of an ILP model. Proceedings of the 2018 20th International Conference on Transparent Optical Networks (ICTON), Bucharest, Romania.","DOI":"10.1109\/ICTON.2018.8473987"},{"key":"ref_36","unstructured":"Ranaweera, C., Nirmalathas, A., Wong, E., Lim, C., Monti, P., Furdek, M., Wosinska, L., Skubic, B., and Machuca, C.M. (2021). Rethinking of Optical Transport Network Design for 5G\/6G Mobile Communication. IEEE Future Netw., 12, Available online: https:\/\/futurenetworks.ieee.org\/tech-focus\/april-2021\/rethinking-ofoptical-transport-network-design-for-5g-6g-mobile-communication."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5100","DOI":"10.1109\/JSYST.2020.2982428","article-title":"Cost-effective migration toward virtualized C-RAN with scalable fronthaul design","volume":"14","author":"Masoudi","year":"2020","journal-title":"IEEE Syst. J."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s13638-020-01844-9","article-title":"Cost-effective joint optimisation of BBU placement and fronthaul deployment in brown-field scenarios","volume":"2020","author":"Marotta","year":"2020","journal-title":"EURASIP J. Wirel. Commun. Netw."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"3850","DOI":"10.1109\/JLT.2015.2443066","article-title":"Cost-optimal placement and backhauling of small-cell networks","volume":"33","author":"Ranaweera","year":"2015","journal-title":"J. Light. Technol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1109\/MCOM.2013.6588652","article-title":"Design and optimization of fiber optic small-cell backhaul based on an existing fiber-to-the-node residential access network","volume":"51","author":"Ranaweera","year":"2013","journal-title":"IEEE Commun. Mag."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Kolydakis, N., and Tomkos, I. (2014, January 6\u201310). A techno-economic evaluation of different strategies for front-\/back-hauling of mobile traffic: Wireless versus fiber based solutions. Proceedings of the 2014 16th International Conference on Transparent Optical Networks (ICTON), Graz, Austria.","DOI":"10.1109\/ICTON.2014.6876350"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Jarray, A., Jaumard, B., and Houle, A.C. (2010, January 23\u201327). Reducing the CAPEX and OPEX costs of optical backbone networks. Proceedings of the 2010 IEEE International Conference on Communications, Cape Town, South Africa.","DOI":"10.1109\/ICC.2010.5501803"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1007\/s12243-016-0538-3","article-title":"Fronthaul network design for radio access network virtualization from a CAPEX\/OPEX perspective","volume":"71","author":"Yeganeh","year":"2016","journal-title":"Ann. Telecommun."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1364\/JOCN.11.000397","article-title":"Cost-optimal deployment of a C-RAN with hybrid fiber\/FSO fronthaul","volume":"11","author":"Tonini","year":"2019","journal-title":"J. Opt. Commun. Netw."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Ar\u00e9valo, G.V., Tip\u00e1n, M., and Gaudino, R. (2018, January 1\u20135). Techno-economics for optimal deployment of optical fronthauling for 5G in large urban areas. Proceedings of the 2018 20th International Conference on Transparent Optical Networks (ICTON), Bucharest, Romania.","DOI":"10.1109\/ICTON.2018.8473801"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Carapellese, N., Tornatore, M., Pattavina, A., and Gosselin, S. (October, January 27). BBU placement over a WDM aggregation network considering OTN and overlay fronthaul transport. Proceedings of the 2015 European Conference on Optical Communication (ECOC), Valencia, Spain.","DOI":"10.1109\/ECOC.2015.7342023"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/0166-218X(84)90088-X","article-title":"Clustering and domination in perfect graphs","volume":"9","author":"Corneil","year":"1984","journal-title":"Discret. Appl. Math."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Qi, J., Yu, Y., Wang, L., and Liu, J. (2016, January 8\u201310). K-means: An effective and efficient K-means clustering algorithm. Proceedings of the 2016 IEEE International Conferences on Big Data and Cloud Computing (BDCloud), Social Computing and Networking (SocialCom), Sustainable Computing and Communications (SustainCom) (BDCloud-SocialCom-SustainCom), Atlanta, GA, USA.","DOI":"10.1109\/BDCloud-SocialCom-SustainCom.2016.46"},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Mirjalili, S. (2019). Genetic algorithm. Evolutionary Algorithms and Neural Networks, Springer.","DOI":"10.1007\/978-3-319-93025-1"},{"key":"ref_50","unstructured":"(2022, November 11). IBM Documentation. Available online: www.ibm.com\/docs\/en\/icos\/12.10.0."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.osn.2014.11.001","article-title":"Optimization of long-reach TDM\/WDM passive optical networks","volume":"16","author":"Buttaboni","year":"2015","journal-title":"Opt. Switch. Netw."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/23\/9394\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:32:24Z","timestamp":1760146344000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/23\/9394"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,1]]},"references-count":51,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2022,12]]}},"alternative-id":["s22239394"],"URL":"https:\/\/doi.org\/10.3390\/s22239394","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,1]]}}}