{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T19:26:13Z","timestamp":1784143573848,"version":"3.55.0"},"reference-count":27,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,6,6]],"date-time":"2023-06-06T00:00:00Z","timestamp":1686009600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Information"],"abstract":"<jats:p>Spread spectrum techniques, such as the Chirp Spread Spectrum (CSS) used by LoRa technology, are important for machine-to-machine communication in the context of the Internet of Things. They offer high processing gain, reliable communication over long ranges, robustness to interference and noise in harsh environments, etc. However, these features are compromised by their poor spectral efficiency, resulting in a very low data transmission rate. This paper deals with a spectrally efficient variant of CSS. The system uses M-ary phase keying to modulate the data and exploits CSS\u2019s properties to transmit the modulated symbols as overlapping chirps. The overlapping of chirp signals may affect the system performance due to inter-symbol interference. Therefore, we analyse the relationship between the number of overlaps and the effect of inter-symbol interference (ISI), and we also determine the BER expression as a function of the number of overlaps. Finally, we derive the optimal number of overlapping symbols that corresponds to the minimum error probability.<\/jats:p>","DOI":"10.3390\/info14060323","type":"journal-article","created":{"date-parts":[[2023,6,7]],"date-time":"2023-06-07T01:38:41Z","timestamp":1686101921000},"page":"323","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["M-Ary Direct Modulation Chirp Spread Spectrum for Spectrally Efficient Communications"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4051-819X","authenticated-orcid":false,"given":"Jocelyn Edinio","family":"Zacko Gbadoubissa","sequence":"first","affiliation":[{"name":"Department of Computer Science, University of Maroua, Maroua P.O. Box 814, Cameroon"},{"name":"African Institute for Mathematical Sciences, Limb\u00e9 P.O. Box 608, Cameroon"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5660-0660","authenticated-orcid":false,"given":"Ado Adamou","family":"Abba Ari","sequence":"additional","affiliation":[{"name":"Department of Computer Science, University of Maroua, Maroua P.O. Box 814, Cameroon"},{"name":"DAVID Lab, University of Versailles Saint-Quentin-en-Yvelines, 45 Avenue des \u00c9tats-Unis, 78000 Versailles, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0819-6285","authenticated-orcid":false,"given":"Emanuel","family":"Radoi","sequence":"additional","affiliation":[{"name":"Lab-STICC, CNRS, Univ Brest, CS 93837, 6 Avenue Le Gorgeu, CEDEX 3, 29238 Brest, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdelhak Mourad","family":"Gueroui","sequence":"additional","affiliation":[{"name":"DAVID Lab, University of Versailles Saint-Quentin-en-Yvelines, 45 Avenue des \u00c9tats-Unis, 78000 Versailles, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,6,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"855","DOI":"10.1109\/TCOM.1982.1095533","article-title":"Theory of spread-spectrum communications-a tutorial","volume":"30","author":"Pickholtz","year":"1982","journal-title":"IEEE Trans. Commun."},{"key":"ref_2","unstructured":"Springer, A., Gugler, W., Huemer, M., Reindl, L., Ruppel, C., and Weigel, R. (2000, January 19). Spread spectrum communications using chirp signals. Proceedings of the IEEE\/AFCEA EUROCOMM 2000. Information Systems for Enhanced Public Safety and Security (Cat. No. 00EX405), Munich, Germany."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.future.2019.11.043","article-title":"HGC: HyperGraph based Clustering scheme for power aware wireless sensor networks","volume":"105","author":"Gbadouissa","year":"2020","journal-title":"Future Gener. Comput. Syst."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1504\/IJSNET.2018.092101","article-title":"Clustering algorithm for wireless sensor networks: The honeybee swarms nest-sites selection process based approach","volume":"27","author":"Ari","year":"2018","journal-title":"Int. J. Sens. Netw."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1109\/MCOMD.1975.1089046","article-title":"Why spread spectrum?","volume":"13","author":"Dixon","year":"1975","journal-title":"Commun. Soc."},{"key":"ref_6","unstructured":"Torrieri, D. (2005). Principles of Spread-Spectrum Communication Systems, Springer."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1109\/TITB.2004.837825","article-title":"A direct-sequence spread-spectrum communication system for integrated sensor microsystems","volume":"9","author":"Aydin","year":"2005","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1109\/ISSSTA.2002.1049289","article-title":"A novel chirp modulation spread spectrum technique for multiple access","volume":"Volume 1","author":"Hengstler","year":"2002","journal-title":"Proceedings of the IEEE Seventh International Symposium on Spread Spectrum Techniques and Applications"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1488","DOI":"10.1109\/LSP.2017.2737596","article-title":"Chirp spread spectrum toward the Nyquist signaling rate\u2014Orthogonality condition and applications","volume":"24","author":"Ouyang","year":"2017","journal-title":"IEEE Signal Process. Lett."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Kim, K.Y., Lee, S.W., and Shin, Y. (2019, January 16\u201318). Spectral Efficiency Improvement of Chirp Spread Spectrum Systems. Proceedings of the 2019 International Conference on Information and Communication Technology Convergence (ICTC), Jeju, Republic of Korea.","DOI":"10.1109\/ICTC46691.2019.8939967"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2965","DOI":"10.1007\/s11277-022-09498-0","article-title":"A Linear Chirp Wireless Transmission Method utilizing Doppler Effect","volume":"124","author":"Qiu","year":"2022","journal-title":"Wirel. Pers. Commun."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"9503","DOI":"10.1109\/JIOT.2019.2929496","article-title":"Efficient Design of Chirp Spread Spectrum Modulation for Low-Power Wide-Area Networks","volume":"6","author":"Nguyen","year":"2019","journal-title":"IEEE Internet Things J."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hosseini, N., and Matolak, D.W. (2019, January 12\u201314). Chirp Spread Spectrum Signaling for Future Air-Ground Communications. Proceedings of the MILCOM 2019-2019 IEEE Military Communications Conference (MILCOM), Norfolk, VA, USA.","DOI":"10.1109\/MILCOM47813.2019.9021056"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1109\/TII.2016.2617921","article-title":"Transmission capacity analysis of relay-assisted device-to-device overlay\/underlay communication","volume":"13","author":"Yang","year":"2016","journal-title":"IEEE Trans. Ind. Inform."},{"key":"ref_15","first-page":"78","article-title":"Fine tuning of data rate enhances performance of a chirp spread spectrum system","volume":"Volume 1","author":"Pohl","year":"1998","journal-title":"Proceedings of the 1998 IEEE 5th International Symposium on Spread Spectrum Techniques and Applications-Proceedings. Spread Technology to Africa (Cat. No. 98TH8333)"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Kim, K.Y., and Shin, Y. (2019, January 2\u20135). Simultaneous Orthogonal Transmission for Direct Modulation Chirp Spread Spectrum Systems. Proceedings of the 2019 Eleventh International Conference on Ubiquitous and Future Networks (ICUFN), Zagreb, Croatia.","DOI":"10.1109\/ICUFN.2019.8806063"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Reynders, B., and Pollin, S. (2016, January 22). Chirp spread spectrum as a modulation technique for long range communication. Proceedings of the 2016 Symposium on Communications and Vehicular Technologies (SCVT), Mons, Belgium.","DOI":"10.1109\/SCVT.2016.7797659"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3110","DOI":"10.1109\/TMC.2021.3051665","article-title":"Boosting chirp signal based aerial acoustic communication under dynamic channel conditions","volume":"21","author":"Cai","year":"2021","journal-title":"IEEE Trans. Mob. Comput."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Ara\u00fajo, D.C., Ferr\u00e9, G., Cavalcante, C.C., and Guerreiro, I.M. (2020, January 18\u201320). A Spectral Efficiency Enhancement for Chirp Spread Spectrum Downlink Communications. Proceedings of the 2020 IEEE Latin-American Conference on Communications (LATINCOM), Santo Domingo, Dominican Republic.","DOI":"10.1109\/LATINCOM50620.2020.9282266"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Azim, A.W., Bazzi, A., Shubair, R., and Chafii, M. (2022). Dual-Mode Chirp Spread Spectrum Modulation. arXiv.","DOI":"10.1109\/LWC.2022.3190564"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2202","DOI":"10.1109\/LWC.2020.3018174","article-title":"Efficient Communications for Overlapped Chirp-Based Systems","volume":"9","author":"Pham","year":"2020","journal-title":"IEEE Wirel. Commun. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1310","DOI":"10.1587\/transcom.E93.B.1310","article-title":"Analysis of Intersymbol Interference due to Overlap in DM-BPSK","volume":"93","author":"Yoon","year":"2010","journal-title":"IEICE Trans. Commun."},{"key":"ref_23","unstructured":"Yoon, T., Yoo, S.H., Kim, S.Y., and Yoon, S. (2008, January 6\u20139). A Closed Form BER expression for an Overlap-based CSS System. Proceedings of the ITC-CSCC: International Technical Conference on Circuits Systems, Computers and Communications, Shimonoseki City, Japan."},{"key":"ref_24","unstructured":"Pinkney, J. (2004). Low Complexity Indoor Wireless Data Links Using Chirp Spread Spectrum. [Ph.D. Thesis, University of Calgary]."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Mumtaz, S., Huq, K.M.S., Radwan, A., Rodriguez, J., and Aguiar, R.L. (2014, January 10\u201314). Energy efficient interference-aware resource allocation in LTE-D2D communication. Proceedings of the 2014 IEEE International Conference on Communications (ICC), Sydney, NSW, Australia.","DOI":"10.1109\/ICC.2014.6883332"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2472","DOI":"10.1109\/TWC.2020.2965443","article-title":"Heterogeneous semi-blind interference alignment in finite-SNR networks with fairness consideration","volume":"19","author":"Yang","year":"2020","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Grami, A. (2015). Passband Digital Transmission, Academic Press. Chapter 7.","DOI":"10.1016\/B978-0-12-407682-2.00007-7"}],"container-title":["Information"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2078-2489\/14\/6\/323\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:49:11Z","timestamp":1760125751000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2078-2489\/14\/6\/323"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,6,6]]},"references-count":27,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2023,6]]}},"alternative-id":["info14060323"],"URL":"https:\/\/doi.org\/10.3390\/info14060323","relation":{},"ISSN":["2078-2489"],"issn-type":[{"value":"2078-2489","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,6,6]]}}}