{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T00:59:25Z","timestamp":1760230765387,"version":"build-2065373602"},"reference-count":53,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2022,8,12]],"date-time":"2022-08-12T00:00:00Z","timestamp":1660262400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004242","name":"Princess Nourah bint Abdulrahman University","doi-asserted-by":"publisher","award":["PNURSP2022R137"],"award-info":[{"award-number":["PNURSP2022R137"]}],"id":[{"id":"10.13039\/501100004242","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Automatic modulation recognition (AMR) is an essential component in the design of smart radios that can intelligently communicate with their surroundings in order to make the most efficient use of available resources. Throughout the last few decades, this issue has been subjected to in-depth examination in the published research literature. To the best of the authors\u2019 knowledge, there have only been a few studies that have been specifically devoted to the task of performing AMR across cooperative wireless transmissions. In this contribution, we examine the AMR problem in the context of amplify-and-forward (AAF) two-path consecutive relaying systems (TCRS) for the first time in the literature. We leverage the property of data redundancy associated with AAF-TCRS signals to design a decision feedback iterative modulation recognizer via an expectation-maximization procedure. The proposed recognizer incorporates the soft information produced by the data detection process as a priori knowledge to generate the a posteriori expectations of the information symbols, which are employed as training symbols. The proposed algorithm additionally involves the development of an estimate of the channel coefficients as a secondary activity. The simulation outcomes have validated the feasibility of the proposed design by demonstrating its capacity to achieve an excellent recognition performance under a wide range of running conditions. According to the findings, the suggested technique converges within six rounds, achieving perfect recognition performance at a signal-to-noise ratio of 14 dB. Furthermore, the minimal pilot-to-frame-size ratio necessary to successfully execute the iterative procedure is 0.07. In addition, the proposed method is essentially immune to time offset and performs well throughout a broad range of frequency offset. Lastly, the proposed strategy beats the existing techniques in recognition accuracy while requiring a low level of processing complexity.<\/jats:p>","DOI":"10.3390\/s22166022","type":"journal-article","created":{"date-parts":[[2022,8,15]],"date-time":"2022-08-15T23:44:03Z","timestamp":1660607043000},"page":"6022","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Decision Feedback Modulation Recognition with Channel Estimation for Amplify and Forward Two-Path Consecutive Relaying Systems"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2105-7239","authenticated-orcid":false,"given":"Mohamed","family":"Marey","sequence":"first","affiliation":[{"name":"Smart Systems Engineering Laboratory, College of Engineering, Prince Sultan University, Riyadh 11586, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9025-0529","authenticated-orcid":false,"given":"Maged Abdullah","family":"Esmail","sequence":"additional","affiliation":[{"name":"Smart Systems Engineering Laboratory, College of Engineering, Prince Sultan University, Riyadh 11586, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7388-8990","authenticated-orcid":false,"given":"Hala","family":"Mostafa","sequence":"additional","affiliation":[{"name":"Department of Information Technology, College of Computer and Information Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"134435","DOI":"10.1109\/ACCESS.2021.3115695","article-title":"Coordinated Allocation of Radio Resources to Wi-Fi and Cellular Technologies in Shared Unlicensed Frequencies","volume":"9","year":"2021","journal-title":"IEEE Access"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1109\/MIM.2015.7066677","article-title":"Signal Identification for Emerging Intelligent Radios: Classical Problems and New Challenges","volume":"18","author":"Dobre","year":"2015","journal-title":"IEEE Instrum. Meas. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1707","DOI":"10.1109\/LCOMM.2021.3054590","article-title":"Turbo Modulation Identification Algorithm for OFDM Software-Defined Radios","volume":"25","author":"Marey","year":"2021","journal-title":"IEEE Commun. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1023","DOI":"10.1109\/LWC.2021.3056453","article-title":"Code-Aided Modulation Classification Algorithm for Multiuser Uplink SC-FDMA Systems","volume":"10","author":"Marey","year":"2021","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1098","DOI":"10.1109\/LSP.2014.2323241","article-title":"Blind Modulation Classification Algorithm for Single and Multiple-Antenna Systems Over Frequency-Selective Channels","volume":"21","author":"Marey","year":"2014","journal-title":"IEEE Signal Process. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4742","DOI":"10.1109\/TIM.2019.2955535","article-title":"A Modulation Classification Algorithm for Multipath Signals Based on Cepstrum","volume":"69","author":"Xing","year":"2020","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1109\/LCOMM.2019.2947043","article-title":"Probabilities of False Alarm and Detection for the First-Order Cyclostationarity Test: Application to Modulation Classification","volume":"24","author":"Serbes","year":"2020","journal-title":"IEEE Commun. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8192","DOI":"10.1109\/TVT.2018.2839735","article-title":"Likelihood-Based Automatic Modulation Classification in OFDM with Index Modulation","volume":"67","author":"Zheng","year":"2018","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5281","DOI":"10.1109\/TVT.2020.2981935","article-title":"Blind Modulation Classification for Asynchronous OFDM Systems Over Unknown Signal Parameters and Channel Statistics","volume":"69","author":"Gupta","year":"2020","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4286","DOI":"10.1109\/TCOMM.2022.3172990","article-title":"Adaptive Opportunistic Spatial Modulation for Boosting Transmit Diversity","volume":"70","author":"He","year":"2022","journal-title":"IEEE Trans. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"818","DOI":"10.1109\/LCOMM.2021.3132947","article-title":"Massive MIMO Adaptive Modulation and Coding Using Online Deep Learning Algorithm","volume":"26","author":"Bobrov","year":"2022","journal-title":"IEEE Commun. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1049\/iet-com:20050176","article-title":"A Survey of Automatic Modulation Classification Techniques: Classical Approaches and New Developments","volume":"1","author":"Dobre","year":"2007","journal-title":"IET Commun."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1109\/LWC.2014.2370034","article-title":"A Bandwidth-Efficient Cognitive Radio with Two-Path Amplify-and-Forward Relaying","volume":"4","author":"Zummo","year":"2015","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_14","unstructured":"Yucek, T., and Arslan, H. (1998, January 19\u201321). OFDM Signal Identification and Transmission Parameter Estimation for Cognitive Radio Applications. Proceedings of the IEEE Military Communications Conference, Boston, MA, USA."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"745","DOI":"10.1109\/LWC.2020.3042384","article-title":"Soft-Information Assisted Modulation Recognition for Reconfigurable Radios","volume":"10","author":"Marey","year":"2021","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Idris, S., Karunathilake, T., and F\u00f6rster, A. (2022). Survey and Comparative Study of LoRa-Enabled Simulators for Internet of Things and Wireless Sensor Networks. Sensors, 22.","DOI":"10.3390\/s22155546"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Hakim, G.P.N., Habaebi, M.H., Toha, S.F., Islam, M.R., Yusoff, S.H.B., Adesta, E.Y.T., and Anzum, R. (2022). Near Ground Pathloss Propagation Model Using Adaptive Neuro Fuzzy Inference System for Wireless Sensor Network Communication in Forest, Jungle and Open Dirt Road Environments. Sensors, 22.","DOI":"10.3390\/s22093267"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Liu, K., Xiang, X., and Yin, L. (2022). Radio Frequency Database Construction and Modulation Recognition in Wireless Sensor Networks. Sensors, 22.","DOI":"10.3390\/s22155715"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Yan, X., Zhang, Y., Rao, X., Wang, Q., Wu, H.C., and Wu, Y. (2022). Novel Cooperative Automatic Modulation Classification Using Vectorized Soft Decision Fusion for Wireless Sensor Networks. Sensors, 22.","DOI":"10.3390\/s22051797"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Markovic, G.B., Sokolovic, V.S., and Dukic, M.L. (2019). Distributed Hybrid Two-Stage Multi-Sensor Fusion for Cooperative Modulation Classification in Large-Scale Wireless Sensor Networks. Sensors, 19.","DOI":"10.3390\/s19194339"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"66496","DOI":"10.1109\/ACCESS.2019.2918136","article-title":"Fusion Methods for CNN-Based Automatic Modulation Classification","volume":"7","author":"Zheng","year":"2019","journal-title":"IEEE Access"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1109\/MSP.2006.1708411","article-title":"Cooperative Diversity for Wireless Ad Hoc Networks","volume":"23","author":"Stankovic","year":"2006","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"25508","DOI":"10.1109\/JSEN.2021.3079331","article-title":"Joint Relay Selection and Adaptive Modulation and Coding for Wireless Cooperative Communications","volume":"21","author":"Xiao","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3191","DOI":"10.1109\/TIFS.2019.2912337","article-title":"Secure Cooperative Communications with an Untrusted Relay: A NOMA-Inspired Jamming and Relaying Approach","volume":"14","author":"Lv","year":"2019","journal-title":"IEEE Trans. Inf. Forensics Secur."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3016","DOI":"10.1109\/TWC.2009.080383","article-title":"Max-min Relay Selection for Legacy Amplify-and-Forward Systems with Interference","volume":"8","author":"Krikidis","year":"2009","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"823","DOI":"10.1109\/TVT.2014.2333417","article-title":"Exact BEP of Decode-and-Forward Cooperative Systems with Multiple Relays in Rayleigh Fading Channels","volume":"64","author":"Kim","year":"2015","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.1109\/LCOMM.2020.3048620","article-title":"Compress-and-Forward Via Multilevel Coding and Trellis Coded Quantization","volume":"25","author":"Wan","year":"2021","journal-title":"IEEE Commun. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1369","DOI":"10.1109\/JPROC.2015.2497203","article-title":"Full-Duplex Wireless Communications: Challenges, Solutions, and Future Research Directions","volume":"104","author":"Zhang","year":"2016","journal-title":"Proc. IEEE"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3447","DOI":"10.1109\/TCOMM.2014.2357423","article-title":"Wireless Information and Power Transfer with Full Duplex Relaying","volume":"62","author":"Zhong","year":"2014","journal-title":"IEEE Trans. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3062","DOI":"10.1109\/TIT.2004.838089","article-title":"Cooperative Diversity in Wireless Networks - Efficient Protocols and Outage Behavior","volume":"50","author":"Laneman","year":"2004","journal-title":"IEEE Trans. Inf. Theory"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1109\/TVT.2010.2090676","article-title":"Full Interference Cancellation for Two-Path Relay Cooperative Networks","volume":"60","author":"Luo","year":"2011","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1708","DOI":"10.1109\/COMST.2015.2424157","article-title":"Non-Coherent Successive Relaying and Cooperation: Principles, Designs, and Applications","volume":"17","author":"Li","year":"2015","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1109\/LWC.2018.2849373","article-title":"Solving IQ Mismatch Problem for Two-Path Successive Relaying OFDMA Uplink Systems with Direct Conversion Transceivers","volume":"8","author":"Marey","year":"2019","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1109\/LCOMM.2019.2901878","article-title":"Iterative Channel Estimation Algorithm for Downlink MC-CDMA Systems with Two-Path Successive Relaying Transmission","volume":"23","author":"Marey","year":"2019","journal-title":"IEEE Commun. Lett."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"4720","DOI":"10.1109\/TWC.2009.081249","article-title":"AF Two-Path Half Duplex Relaying with Inter-Relay Self Interference Cancellation: Diversity Analysis and its Improvement","volume":"8","author":"Wicaksana","year":"2009","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1109\/JSAC.2007.070213","article-title":"Spectral Efficient Protocols for Half Duplex Fading Relay Channels","volume":"25","author":"Rankov","year":"2007","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"4484","DOI":"10.1109\/TWC.2007.060339","article-title":"Recovering Multiplexing Loss through Successive Relaying Using Repetition Coding","volume":"6","author":"Fan","year":"2007","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1899","DOI":"10.1049\/iet-com.2013.0206","article-title":"Simplified Maximum-likelihood Detectors for Full-rate Alternate-relaying Cooperative Systems","volume":"7","author":"Mostafa","year":"2013","journal-title":"IET Commun."},{"key":"ref_39","first-page":"1","article-title":"Decoding Techniques for Alternate-Relaying Cooperative Systems","volume":"1","author":"Mostafa","year":"2013","journal-title":"EURASIP J. Wirel. Commun. Netw."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2017","DOI":"10.1109\/LWC.2021.3090938","article-title":"Iterative Modulation Classification Algorithm for Two-Path Successive Relaying Systems","volume":"10","author":"Marey","year":"2021","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"2369","DOI":"10.1109\/LWC.2021.3100813","article-title":"Blind Modulation Identification Algorithm For Two-Path Successive Relaying Systems","volume":"10","author":"Marey","year":"2021","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1109\/TVT.2021.3130061","article-title":"Message Passing-Based Impulsive Noise Mitigation and Channel Estimation for Underwater Acoustic OFDM Communications","volume":"71","author":"Feng","year":"2022","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"548","DOI":"10.1109\/TWC.2021.3098241","article-title":"Joint Synchronization and Compressive Channel Estimation for Frequency-Selective Hybrid mmWave MIMO Systems","volume":"21","author":"Fernandez","year":"2022","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"3802","DOI":"10.1109\/TVT.2015.2438113","article-title":"Data Detection Algorithms for BICM Alternate-Relaying Cooperative Systems with Multiple-Antenna Destination","volume":"65","author":"Marey","year":"2016","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"936","DOI":"10.1109\/TBC.2016.2606892","article-title":"Iterative Receiver Design for Uplink OFDMA Cooperative Systems","volume":"62","author":"Marey","year":"2016","journal-title":"IEEE Trans. Broadcast."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2574","DOI":"10.1109\/TWC.2012.041612.111488","article-title":"Classification of Space-time Block Codes Based on Second-order Cyclostationarity with Transmission Impairments","volume":"11","author":"Marey","year":"2012","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Marey, M., Dobre, O.A., and Inkol, R. (2012, January 10\u201315). Cyclostationarity-Based Blind Classification of STBCs for Cognitive Radio Systems. Proceedings of the IEEE International Conference on Communications, Ottawa, ON, Canada.","DOI":"10.1109\/ICC.2012.6363735"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"2706","DOI":"10.1109\/TWC.2014.033114.130726","article-title":"Novel Data Detection and Channel Estimation Algorithms for BICM OFDMA Uplink Asynchronous Systems in the Presence of IQ Imbalance","volume":"13","author":"Marey","year":"2014","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1002","DOI":"10.1109\/LCOMM.2018.2806964","article-title":"Low Complexity IQ Mismatch Compensation Algorithm with Channel Awareness for Two-Path Successive Relay Networks","volume":"22","author":"Marey","year":"2018","journal-title":"IEEE Commun. Lett."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1109\/LWC.2015.2451174","article-title":"Blind Modulation Classification for Alamouti STBC System with Transmission Impairments","volume":"4","author":"Marey","year":"2015","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"657","DOI":"10.1109\/LSP.2008.2004517","article-title":"Code-Aided Channel Tracking and Frequency Offset-Phase Noise Elimination for Multi-Carrier Systems","volume":"15","author":"Marey","year":"2008","journal-title":"IEEE Signal Process. Lett."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Marey, M., and Steendam, H. (2006, January 25\u201328). The Effect of Narrowband Interference on Frequency Ambiguity Resolution for OFDM. Proceedings of the IEEE Vehicular Technology Conference, Montreal, QC, Canada.","DOI":"10.1109\/VTCF.2006.342"},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Bedeer, E., Marey, M., Dobre, O., and Baddour, K. (2012, January 15\u201318). Adaptive Bit Allocation for OFDM Cognitive Radio Systems with Imperfect Channel Estimation. Proceedings of the IEEE Radio and Wireless Symposium, Santa Clara, CA, USA.","DOI":"10.1109\/RWS.2012.6175359"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/16\/6022\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:07:45Z","timestamp":1760141265000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/16\/6022"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,12]]},"references-count":53,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["s22166022"],"URL":"https:\/\/doi.org\/10.3390\/s22166022","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,8,12]]}}}