{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:00:47Z","timestamp":1760230847967,"version":"build-2065373602"},"reference-count":38,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2022,8,11]],"date-time":"2022-08-11T00:00:00Z","timestamp":1660176000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Natural Science Foundation of Fujian Province, China","award":["2018J01569"],"award-info":[{"award-number":["2018J01569"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>To reduce the waste of energy in communications, unequal error protection (UEP) is used to provide asymmetric protection for messages with different levels of importance. This paper proposes new efficient strategies of UEP based on bilayer protograph-based low-density parity check (PLDPC) codes in decoding-and-forward (DF) relay systems. In particular, we jointly utilize source coding and channel coding to design UEP strategies and then save transmission energy. According to the different levels of importance of discrete cosine transform (DCT) coefficients of image and variance statistical characteristics of image sub-blocks, bilayer-lengthened PLDPC codes are exploited to protect the transmitted image information with different importance levels at the half-duplex relay system. In the end, the simulation result shows that the proposed UEP schemes achieve excellent performance gains compared to conventional equal error protection (EEP) scheme. Additionally, the complexity analysis of the UEP strategies is given.<\/jats:p>","DOI":"10.3390\/sym14081662","type":"journal-article","created":{"date-parts":[[2022,8,11]],"date-time":"2022-08-11T23:05:49Z","timestamp":1660259149000},"page":"1662","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["New Unequal Error Protection Strategy for Image Transmission Based on Bilayer-Lengthened PLDPC Code in Half-Duplex Relay System"],"prefix":"10.3390","volume":"14","author":[{"given":"Tian","family":"Gao","sequence":"first","affiliation":[{"name":"School of OPTO-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361005, China"}]},{"given":"Min","family":"Xiao","sequence":"additional","affiliation":[{"name":"School of OPTO-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361005, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2876-653X","authenticated-orcid":false,"given":"Pingping","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Physics and Information Engineering, Fuzhou University, Fuzhou 350108, China"}]},{"given":"Diyan","family":"Gao","sequence":"additional","affiliation":[{"name":"Maynooth International School of Engineering, Fuzhou University, Fuzhou 350108, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3157","DOI":"10.1109\/TWC.2016.2517623","article-title":"Outage Analysis of Co-Operative Two-Path Relay Channels","volume":"15","author":"Li","year":"2016","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1109\/MNET.001.1900289","article-title":"Physical-Layer Network Coding: An Efficient Technique for Wireless Communications","volume":"34","author":"Chen","year":"2020","journal-title":"IEEE Netw."},{"key":"ref_3","first-page":"147","article-title":"Bandwidth-Efficient Coded Modulation Schemes for Physical-Layer Network Coding with High-Order Modulations","volume":"65","author":"Chen","year":"2017","journal-title":"IEEE Trans. Commun."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1109\/TWC.2006.1611050","article-title":"Diversity through Coded Cooperation","volume":"5","author":"Hunter","year":"2006","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1109\/MWC.2011.5714021","article-title":"Mixing Network Coding and Cooperation for Reliable Wireless Communications","volume":"18","author":"Rossetto","year":"2011","journal-title":"IEEE Wirel. Commun."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/j.phycom.2012.04.006","article-title":"Joint Utility-Based Uplink Power and Rate Allocation in Wireless Networks: A non-cooperative game theoretic framework","volume":"9","author":"Tsiropoulou","year":"2013","journal-title":"Phys. Commun."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"El-ghorab, M.A., El-meligy, M.R., Ibrahim, M.M., and Newagy, F. (2022). Energy-Efficient User Pairing for Downlink NOMA in Massive MIMO Networks. Appl. Sci., 12.","DOI":"10.3390\/app12115421"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Ali, Z.J., Noordin, N.K., Sali, A., Hashim, F., and Balfaqih, M. (2020). Novel Resource Allocation Techniques for Downlink Non-Orthogonal Multiple Access Systems. Appl. Sci., 10.","DOI":"10.3390\/app10175892"},{"key":"ref_9","unstructured":"Zhao, M., and Akansu, A.N. (2000, January 24\u201328). UEP of progressive images in wireless channels. Proceedings of the Vehicular Technology Conference Fall 2000, Boston, MA, USA."},{"key":"ref_10","unstructured":"Zhao, M., and Akansu, A.N. (2000, January 10\u201313). Optimization of dynamic UEP schemes for embedded image sources in noisy channels. Proceedings of the International Conference on Image Processing (ICIP), Vancouver, BC, Canada."},{"key":"ref_11","unstructured":"Yang, X., Yuan, D., Ma, P., and Jiang, M. (2004, January 5\u20138). New research on unequal error protection (UEP) property of irregular LDPC codes. Proceedings of the First IEEE Consumer Communications and Networking Conference (CCNC), Las Vegas, NV, USA."},{"key":"ref_12","unstructured":"Ma, P., and Kwak, K.S. (2009, January 28\u201330). Modulation-assisted UEP-LDPC codes in image transmission. Proceedings of the 9th International Symposium on Communications and Information Technology (ISCIT), Icheon, Korea."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3556","DOI":"10.1109\/TCOMM.2021.3064941","article-title":"Design and Analysis of Delayed Bit-Interleaved Coded Modulation with LDPC Codes","volume":"69","author":"Liao","year":"2021","journal-title":"IEEE Trans. Commun."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Xu, B., Zhang, Z.M., Zhang, E.Y., and He, Y.L. (2009, January 17\u201319). Research on Unequal Error Protection with Irregular LDPC and Application on Image Transmission. Proceedings of the 2nd International Congress on Image and Signal Processing (ICISP), Tianjin, China.","DOI":"10.1109\/CISP.2009.5301164"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Zhang, W., Jing, X., Zhang, Z., and Chen, Q. (2013, January 16\u201318). Image transmission with UEP-LT over MIMO channels. Proceedings of the 22nd Wireless and Optical Communication Conference (WOCC), Chongqing, China.","DOI":"10.1109\/WOCC.2013.6676350"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3575","DOI":"10.1109\/LCOMM.2021.3108845","article-title":"Autoencoder-Based Unequal Error Protection Code","volume":"25","author":"Ninkovic","year":"2021","journal-title":"IEEE Commun. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"101721","DOI":"10.1016\/j.phycom.2022.101721","article-title":"A type-aware coding approach for unequal message protection","volume":"53","author":"Yao","year":"2022","journal-title":"Phys. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1109\/4234.905935","article-title":"On the Design of Low-density Parity-check Codes within 0.0045 dB of the Shannon Limit","volume":"5","author":"Chung","year":"2001","journal-title":"IEEE Commun. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"908","DOI":"10.1109\/49.924874","article-title":"Iterative reliability-based decoding of low-density parity check codes","volume":"5","author":"Fossorier","year":"2001","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"11033","DOI":"10.1109\/TVT.2021.3106053","article-title":"Protograph LDPC-Coded BICM-ID With Irregular CSK Mapping in Visible Light Communication Systems","volume":"70","author":"Dai","year":"2021","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1027","DOI":"10.1109\/TCSI.2012.2209304","article-title":"One Analog STBC-DCSK Transmission Scheme not Requiring Channel State Information","volume":"60","author":"Chen","year":"2013","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1112","DOI":"10.1109\/LCOMM.2018.2814985","article-title":"Rate-Adaptive Protograph LDPC Codes for Multi-Level-Cell NAND Flash Memory","volume":"22","author":"Chen","year":"2018","journal-title":"IEEE Commun. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"75264","DOI":"10.1109\/ACCESS.2020.2988510","article-title":"Artificial Intelligence in Education: A Review","volume":"8","author":"Chen","year":"2020","journal-title":"IEEE Access"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Chen, C., Xiang, J., Ye, Z., Yan, W., Wang, S., Wang, Z., Chen, P., and Xiao, M. (2022). Deep Learning-Based Energy Optimization for Edge Device in UAV-Aided Communications. Drones, 6.","DOI":"10.3390\/drones6060139"},{"key":"ref_25","unstructured":"Fang, Y., Bu, Y., Chen, P., Lau, F.C.M., and Otaibi, S.A. (2021). Irregular-Mapped Protograph LDPC-Coded Modulation: A Bandwidth-Efficient Solution for 6G-Enabled Mobile Networks. IEEE Trans. Intell. Transp. Syst., early access."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3723","DOI":"10.1109\/TIT.2007.904983","article-title":"Bilayer Low-density Parity-check Codes for Decode-and-Forward in Relay Channels","volume":"53","author":"Razaghi","year":"2007","journal-title":"IEEE Trans. Inf. Theory"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Vahabzadeh, O., and Salehi, M. (2011, January 23\u201325). Design of bilayer lengthened LDPC codes for Rayleigh fading relay channels. Proceedings of the 45th Annual Conference on Information Sciences and Systems, Baltimore, MD, USA.","DOI":"10.1109\/CISS.2011.5766201"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1969","DOI":"10.1109\/TWC.2013.040413.111745","article-title":"Bilayer protograph codes for half-duplex relay channels","volume":"12","author":"Nosratinia","year":"2013","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1989","DOI":"10.1109\/COMST.2015.2436705","article-title":"A survey on protograph LDPC codes and their applications","volume":"17","author":"Fang","year":"2015","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1983","DOI":"10.1109\/JSAC.2021.3078488","article-title":"Learning to decode protograph LDPC codes","volume":"39","author":"Dai","year":"2021","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1109\/TIT.1979.1056084","article-title":"Capacity theorems for the relay channel","volume":"25","author":"Cover","year":"1979","journal-title":"IEEE Trans. Inf. Theory"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1236","DOI":"10.1109\/TCSVT.2004.835151","article-title":"Scalable Variable Complexity Approximate forward DCT","volume":"14","author":"Lengwehasatit","year":"2004","journal-title":"IEEE Trans. Circuits Syst. Video Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1109\/TCSVT.2002.804880","article-title":"Blocking Artifact Detection and Reduction in Compressed Data","volume":"12","author":"Triantafyllidis","year":"2002","journal-title":"IEEE Trans. Circuits Syst. Video Technol."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Banerjee, S., Choudhary, A., and Pal, S. (2016, January 19\u201321). Empirical Evaluation of K-Means, Bisecting K-Means, Fuzzy C-Means and Genetic K-Means Clustering Algorithms. Proceedings of the IEEE International WIE Conference on Electrical and Computer Engineering (WIECON-ECE), Pune, India.","DOI":"10.1109\/WIECON-ECE.2015.7443889"},{"key":"ref_35","first-page":"41","article-title":"Images as Graphical Password: Verification and analysis using non-regular low-density parity check coding","volume":"1","author":"Singh","year":"2020","journal-title":"Int. J. Inf. Technol."},{"key":"ref_36","first-page":"533","article-title":"Image Segmentation Using Computational Intelligence Techniques: Review","volume":"64","author":"Chouhan","year":"2018","journal-title":"Arch. Comput. Methods Eng."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"28483","DOI":"10.1007\/s11042-018-6005-6","article-title":"Soft computing approaches for image segmentation: A survey","volume":"77","author":"Chouhan","year":"2018","journal-title":"Multimed. Tools Appl."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"35263","DOI":"10.1007\/s11042-019-08094-y","article-title":"Image segmentation using fuzzy competitive learning based counter propagation network","volume":"5","author":"Chouhan","year":"2019","journal-title":"Multimed. Tools Appl."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/14\/8\/1662\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:07:11Z","timestamp":1760141231000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/14\/8\/1662"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,11]]},"references-count":38,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["sym14081662"],"URL":"https:\/\/doi.org\/10.3390\/sym14081662","relation":{},"ISSN":["2073-8994"],"issn-type":[{"type":"electronic","value":"2073-8994"}],"subject":[],"published":{"date-parts":[[2022,8,11]]}}}