{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:59:30Z","timestamp":1760147970143,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,21]],"date-time":"2023-03-21T00:00:00Z","timestamp":1679356800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Internal Affairs and Communications in Japan under the Strategic Information and Communications R &amp; D Promotion Programme","award":["SCOPE JP205004001","JP21H01322"],"award-info":[{"award-number":["SCOPE JP205004001","JP21H01322"]}]},{"name":"JSPS KAKENHI","award":["SCOPE JP205004001","JP21H01322"],"award-info":[{"award-number":["SCOPE JP205004001","JP21H01322"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In recent years, there have been increased demands for aggregating sensor information from several sensors owing to the spread of the Internet of Things (IoT). However, packet communication, which is a conventional multiple-access technology, is hindered by packet collisions owing to simultaneous access by sensors and waiting time to avoid packet collisions; this increases the aggregation time. The physical wireless parameter conversion sensor network (PhyC-SN) method, which transmits sensor information corresponding to the carrier wave frequency, facilitates the bulk collection of sensor information, thereby reducing the communication time and achieving a high aggregation success rate. However, when more than one sensor transmits the same frequency simultaneously, the estimation accuracy of the number of accessed sensors deteriorates significantly because of multipath fading. Thus, this study focuses on the phase fluctuation of the received signal caused by the frequency offset inherent to the sensor terminals. Consequently, a new feature for detecting collisions is proposed, which is a case in which two or more sensors transmit simultaneously. Furthermore, a method to identify the existence of 0, 1, 2, or more sensors is established. In addition, we demonstrate the effectiveness of PhyC-SNs in estimating the location of radio transmission sources by utilizing three patterns of 0, 1, and 2 or more transmitting sensors.<\/jats:p>","DOI":"10.3390\/s23063308","type":"journal-article","created":{"date-parts":[[2023,3,21]],"date-time":"2023-03-21T06:56:48Z","timestamp":1679381808000},"page":"3308","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Three Level Recognition Based on the Average of the Phase Differences in Physical Wireless Parameter Conversion Sensor Networks and Its Effect to Localization with RSSI"],"prefix":"10.3390","volume":"23","author":[{"given":"Toshi","family":"Ito","sequence":"first","affiliation":[{"name":"Department of Electrical & Computer Engineering, Shinshu University, Nagano 380-8553, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masafumi","family":"Oda","sequence":"additional","affiliation":[{"name":"Department of Electrical & Computer Engineering, Shinshu University, Nagano 380-8553, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3221-6714","authenticated-orcid":false,"given":"Osamu","family":"Takyu","sequence":"additional","affiliation":[{"name":"Department of Electrical & Computer Engineering, Shinshu University, Nagano 380-8553, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mai","family":"Ohta","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering and Computer Science, Fukuoka University, Fukuoka 814-0180, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7886-5560","authenticated-orcid":false,"given":"Takeo","family":"Fujii","sequence":"additional","affiliation":[{"name":"Advanced Wireless & Communication Research Center, University of Electrocommunications, Tokyo 182-8585, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Koichi","family":"Adachi","sequence":"additional","affiliation":[{"name":"Advanced Wireless & Communication Research Center, University of Electrocommunications, Tokyo 182-8585, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1109\/MMM.2017.2740738","article-title":"Weaving the Wireless Web: Toward a Low-Power, Dense Wireless Sensor Network for the Industrial IoT","volume":"18","author":"Williams","year":"2017","journal-title":"IEEE Microw. Mag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1016\/j.sigpro.2013.07.018","article-title":"Selective forwarding for energy-efficient target tracking in sensor networks","volume":"94","year":"2014","journal-title":"Signal Process"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1109\/JIOT.2015.2498900","article-title":"Middleware for Internet of Things: A survey","volume":"3","author":"Razzaque","year":"2016","journal-title":"IEEE Internet Things J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"15070","DOI":"10.1109\/JIOT.2020.3026730","article-title":"SWIPT Cooperative Spectrum Sharing for 6G-Enabled Cognitive IoT Network","volume":"8","author":"Lu","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"31457","DOI":"10.1109\/ACCESS.2018.2839669","article-title":"5G optimized caching and downlink resource sharing for smart cities","volume":"6","author":"Vo","year":"2018","journal-title":"IEEE Access"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1449","DOI":"10.1587\/transcom.E97.B.1449","article-title":"A pseudo-TDMA MAC protocol using randomly determined transmission times for landslide prediction wireless sensor networks","volume":"E97-B","author":"Asano","year":"2014","journal-title":"IEICE Trans. Commun."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1198","DOI":"10.1587\/transcom.2020DSI0001","article-title":"Research & Development of the advanced dynamic spectrum sharing system between different radio services","volume":"E104-B","author":"Shinbo","year":"2021","journal-title":"IEICE Trans. Commun."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Suehiro, T., Kobayashi, T., Takyu, O., and Fuwa, Y. (IEICE Trans. Commun., 2023). Data gathering scheme for event detection and recognition in low-power wide area networks, IEICE Trans. Commun., early access.","DOI":"10.1587\/transcom.2022EBP3153"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Sa-Ingthong, J., Phonphoem, A., Jansang, A., and Jaikaeo, C. (2021, January 21\u201324). Probabilistic analysis of packet losses in dense LoRa Nntworks. Proceedings of the 2021 13th International Conference on Knowledge and Smart Technology (KST), Bangsaen, Chonburi, Thailand.","DOI":"10.1109\/KST51265.2021.9415774"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Pandey, D., Kalbande, D., and Kamble, V. (2015, January 23\u201324). Comparative analysis of carrier sense multiple access and carrier sense multiple access with shortest first. Proceedings of the 2015 Global Conference on Communication Technologies (GCCT), Thuckalay, India.","DOI":"10.1109\/GCCT.2015.7342734"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Dholey, M.K., and Khatun, A. (2012, January 6\u20138). Reduction of blockage node and hidden terminal problem of CSMA\/CA MAC protocol using directional antenna. Proceedings of the 2012 2nd IEEE International Conference on Parallel, Distributed and Grid Computing, Solan, India.","DOI":"10.1109\/PDGC.2012.6449914"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"6369","DOI":"10.1109\/JIOT.2020.2972274","article-title":"Deep reinforcement learning for throughput improvement of the uplink grant-free NOMA system","volume":"7","author":"Zhang","year":"2020","journal-title":"IEEE Internet Things J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"44645","DOI":"10.1109\/ACCESS.2019.2909525","article-title":"Adaptive channel assignment with predictions of sensor results and channel occupancy ratio in PhyC-SN","volume":"7","author":"Takyu","year":"2019","journal-title":"IEEE Access"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"12843","DOI":"10.1109\/ACCESS.2023.3242611","article-title":"Position estimation of radio source based on fingerprinting with physical wireless parameter conversion sensor networks","volume":"11","author":"Oda","year":"2023","journal-title":"IEEE Access"},{"key":"ref_15","unstructured":"Kay, S.M. (1998). Fundamentals of Statistical Signal Processing, Prentice Hall."},{"key":"ref_16","unstructured":"Nee, R.V., and Prasad, R. (2000). Artech House."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"822","DOI":"10.1109\/TWC.2003.814346","article-title":"A robust timing and frequency synchronization for OFDM systems","volume":"2","author":"Minn","year":"2003","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Ito, T., Takyu, O., Ohta, M., Fujii, T., and Adachi, K. (2022, January 5\u20138). High-sensitivity detection method for signals in PhyC-SN. Proceedings of the 2022 Thirteenth International Conference on Ubiquitous and Future Networks (ICUFN), Barcelona, Spain.","DOI":"10.1109\/ICUFN55119.2022.9829661"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1284","DOI":"10.1109\/LCOMM.2013.020413.122318","article-title":"Carrier sense multiple access with collision resolution","volume":"17","author":"Choi","year":"2013","journal-title":"IEEE Commun. Lett."},{"key":"ref_20","first-page":"57","article-title":"Primary user detection under superposed TD-LTE Signal","volume":"120","author":"Nakano","year":"2020","journal-title":"IEICE Tech. Rep."},{"key":"ref_21","unstructured":"Yu, G., and Long, C. (2011, January 27\u201329). Research on energy detection algorithm in cognitive radio systems. Proceedings of the 2011 International Conference on Computer Science and Service System (CSSS), Nanjing, China."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Parvathy, A., and Narayanan, G. (2020, January 25\u201326). Comparative study of energy detection and matched filter based spectrum sensing techniques. Proceedings of the 2020 12th International Conference on Computational Intelligence and Communication Networks (CICN), Bhimtal, India.","DOI":"10.1109\/CICN49253.2020.9242609"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Narieda, S., and Hada, T. (2014, January 19\u201321). Experimental analyses of spectrum sensing using cyclic autocorrelation function diversity combining techniques in cognitive radio. Proceedings of the 2014 IEEE International Conference on Communication Systems, Macau, China.","DOI":"10.1109\/ICCS.2014.7024828"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Kavitha, K., Thilagavathi, K., Dhivyapraba, R., Jasmine, K., and Sugumar, D. (2022, January 21\u201322). Non-orthogonal multiple access (NOMA) signal detection using SVM over Rayleigh fading channel. Proceedings of the 2022 6th International Conference on Devices, Circuits and Systems (ICDCS), Coimbatore, India.","DOI":"10.1109\/ICDCS54290.2022.9780685"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"12","DOI":"10.23919\/JCC.2020.11.002","article-title":"Active user and data detection for uplink grant-free NOMA systems","volume":"17","author":"Cai","year":"2020","journal-title":"China Commun."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Chen, S., Xie, F., Chen, Y., Song, H., and Wen, H. (2017, January 28\u201331). Identification of wireless transceiver devices using radio frequency (RF) fingerprinting based on STFT analysis to enhance authentication security. Proceedings of the 2017 IEEE 5th International Symposium on Electromagnetic Compatibility (EMC-Beijing), Beijing, China.","DOI":"10.1109\/EMC-B.2017.8260381"},{"key":"ref_27","unstructured":"Giniatullin, N.F., Glushankov, E.I., and Marchuk, L.A. (1996, January 18). Control algorithm of adaptive antenna arrays for signal and interference separation. Proceedings of the Third International Conference on Signal Processing (ICSP\u201996), Beijing, China."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"946760","DOI":"10.1155\/2015\/946760","article-title":"Data tracking and effect of frequency offset to simultaneous collecting method for wireless sensor networks","volume":"2015","author":"Myoenzono","year":"2015","journal-title":"Int. J. Distrib. Sens. Netw."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1670","DOI":"10.1109\/TIM.2009.2014506","article-title":"New spectrum leakage correction algorithm for frequency estimation of power system signals","volume":"58","author":"Radil","year":"2009","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_30","unstructured":"He, L., and Kuo, G.-S. (2006, January 7\u201310). A Novel Time Synchronization Scheme in Wireless Sensor Networks. Proceedings of the 2006 IEEE 63rd Vehicular Technology Conference, Melbourne, VIC, Australia."},{"key":"ref_31","first-page":"1495","article-title":"Frequency offset compensation with MMSE-MUD for multi-carrier CDMA in quasi-synchronous uplink","volume":"E87-B","author":"Takyu","year":"2004","journal-title":"IEICE Trans. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Hastie, T., Tibshirani, R., and Friedman, J. (2009). The Elements of Statistical Learning, Data Mining, Inference, and Prediction, Springer.","DOI":"10.1007\/978-0-387-84858-7"},{"key":"ref_33","unstructured":"(2022, July 01). fitcecoc\u2014Support Vector Machine Classification\u2014MathWorks. Available online: https:\/\/jp.mathworks.com\/help\/stats\/fitcecoc.html."},{"key":"ref_34","unstructured":"Iwai, M. (2012). Radio Propagation in Mobile Communications\u2014Fundamental Knowledge for Simulation Analysis of Wireless Communications, Corona Publishing."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/6\/3308\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:59:39Z","timestamp":1760122779000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/6\/3308"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,21]]},"references-count":34,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2023,3]]}},"alternative-id":["s23063308"],"URL":"https:\/\/doi.org\/10.3390\/s23063308","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2023,3,21]]}}}