{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T06:12:57Z","timestamp":1763705577848,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2019,4,25]],"date-time":"2019-04-25T00:00:00Z","timestamp":1556150400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61671050"],"award-info":[{"award-number":["61671050"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Low-Power Wide-Area Network (LPWAN) is the technology that the Internet-of-Things (IoT) uses in long-distance, wide-coverage scenarios. As one of the ultra-narrowband (UNB) modulation techniques, M-ary position phase shift keying (MPPSK) modulation can provide high coverage and high reliability for LPWAN. This paper proposes a multipath separation method based on MPPSK modulation, which aims to eliminate the influence of multipath on the main path without increasing the spectrum overhead and system complexity. Specifically, the modulation parameter of the system is adjusted according to the delay value, so that the phase jump of the multipath signal falls outside the phase jump of the main path symbol to achieve separation of the multipath from the main path. Moreover, a normalized symbol joint decision method is proposed in order to reduce the introduced noise while using multipath information for decisions. The simulation results indicate that the multipath separation conditions given in this paper can meet the requirements of multipath separation of MPPSK signals. Compared with the existing mainstream decision scheme, the normalized symbol joint decision improves the demodulation performance of the system.<\/jats:p>","DOI":"10.3390\/s19081938","type":"journal-article","created":{"date-parts":[[2019,4,25]],"date-time":"2019-04-25T03:39:02Z","timestamp":1556163542000},"page":"1938","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Anti-Multipath Performance Improvement of an M-ary Position Phase Shift Keying Modulation System"],"prefix":"10.3390","volume":"19","author":[{"given":"Haiyuan","family":"Wang","sequence":"first","affiliation":[{"name":"School of Electronic and Information Engineering Beijing Jiaotong University, Beijing 100044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1719-9314","authenticated-orcid":false,"given":"Hongxian","family":"Tian","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering Beijing Jiaotong University, Beijing 100044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,4,25]]},"reference":[{"doi-asserted-by":"crossref","unstructured":"Goursaud, C., and Mo, Y. (2016, January 16\u201318). Random unslotted time-frequency ALOHA: Theory and application to IoT UNB networks. Proceedings of the 2016 23rd International Conference on Telecommunications (ICT), Thessaloniki, Greece.","key":"ref_1","DOI":"10.1109\/ICT.2016.7500489"},{"doi-asserted-by":"crossref","unstructured":"Mo, Y., Goursaud, C., and Gorce, J.M. (2016, January 4\u20138). Theoretical analysis of UNB-based IoT networks with path loss and random spectrum access. Proceedings of the 2016 IEEE 27th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Valencia, Spain.","key":"ref_2","DOI":"10.1109\/PIMRC.2016.7794608"},{"unstructured":"(2019, March 07). What Is LPWAN?. Available online: https:\/\/5g.co.uk\/guides\/what-is-lpwan\/.","key":"ref_3"},{"doi-asserted-by":"crossref","unstructured":"Naik, N. (2018, January 1\u20133). LPWAN Technologies for IoT Systems: Choice between Ultra Narrow Band and Spread Spectrum. 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