{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:30:57Z","timestamp":1760236257737,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2021,11,5]],"date-time":"2021-11-05T00:00:00Z","timestamp":1636070400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the National Natural Science Foundation of China","award":["61931009","61971450"],"award-info":[{"award-number":["61931009","61971450"]}]},{"name":"Science and Technology Planning Program of Yongzhou City under Grant","award":["2020-YZKJ-010"],"award-info":[{"award-number":["2020-YZKJ-010"]}]},{"name":"the Research Foundation of Education Department of Hunan Province","award":["18B517"],"award-info":[{"award-number":["18B517"]}]},{"name":"the Research Foundation of China Postdoctoral Science Foundation","award":["2019M652895"],"award-info":[{"award-number":["2019M652895"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Improving spectral efficiency under a certain energy limitation is an important design metric for future wireless communications as a response to the growing transmission demand of wireless devices. In order to improve spectral efficiency for communication systems without increasing energy consumption, this paper considers a non-orthogonal multiple access (NOMA)\u2013based cognitive radio network, with the assistance of a wireless-powered relay station (RS), and then analyzes the system outage performance under amplified-and-forward (AF) and decoded-and-forward (DF) cooperative transmission modes. Specifically, the base station (BS) has the opportunity to cooperate by transmitting information through the RS, depending on whether the RS can harvest sufficient RF energy for cooperative transmission. That is to say, when the energy stored by the RS is sufficient for cooperative transmission, the RS will assist the BS to forward information; otherwise, the BS will send information through direct links, while the RS converts the radio frequency (RF) signals sent by the BS into energy for future transmission. Moreover, the transmission power required by the RS for cooperative transmission is usually relatively large, while the amount of harvested energy by the RS in a transmission slot is usually low, so it takes several consecutive time slots to accumulate enough transmission energy. To this end, we utilize a discrete-time Markov chain to describe the processes of charging and discharging of the RS. Subsequently, we derive the closed-form outage probabilities of both the primary and secondary systems for the considered system in AF and DF modes through mathematical analysis, and verify the accuracy of the analyses through Monte Carlo simulation. The simulation results show that the two proposed cooperative transmission schemes with AF and DF relaying techniques outperform both direct transmission and other similar schemes in both the primary and secondary system, while the DF scheme can provide better performance than the AF scheme within the range of setting values.<\/jats:p>","DOI":"10.3390\/e23111463","type":"journal-article","created":{"date-parts":[[2021,11,5]],"date-time":"2021-11-05T10:33:09Z","timestamp":1636108389000},"page":"1463","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Outage Performance Analysis of NOMA in Wireless Powered Cognitive Radio Networks with AF and DF Relaying Techniques"],"prefix":"10.3390","volume":"23","author":[{"given":"Hui","family":"Wang","sequence":"first","affiliation":[{"name":"School of Computer Science and Engineering, Central South University, No. 932 Lushannan Road, Changsha 410083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8220-8424","authenticated-orcid":false,"given":"Jian","family":"Dong","sequence":"additional","affiliation":[{"name":"School of Computer Science and Engineering, Central South University, No. 932 Lushannan Road, Changsha 410083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6993-5347","authenticated-orcid":false,"given":"Kun","family":"Tang","sequence":"additional","affiliation":[{"name":"Guangdong Provincial Key Laboratory of Millimeter-Wave and Terahertz, School of Electronic and Information Engineering, South China University of Technology, No. 381 Wushan Road, Guangzhou 510640, China"},{"name":"College of Intelligent Manufacturing, Hunan University of Science and Engineering, Yongzhou 425000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9040-7247","authenticated-orcid":false,"given":"Heyuan","family":"Shi","sequence":"additional","affiliation":[{"name":"School of Software, Tsinghua University, Beijing 100084, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1109\/OJCOMS.2020.2969899","article-title":"A Survey of NOMA: Current Status and Open Research Challenges","volume":"1","author":"Makki","year":"2020","journal-title":"IEEE Open J. Commun. Soc."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"74288","DOI":"10.1109\/ACCESS.2018.2884014","article-title":"Performance Analysis of User Pairing in Cooperative NOMA Networks","volume":"6","author":"Zhang","year":"2018","journal-title":"IEEE Access"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"120","DOI":"10.23919\/JCC.2019.11.010","article-title":"Performance analysis of cooperative NOMA with energy harvesting in multi-cell networks","volume":"16","author":"Guo","year":"2019","journal-title":"China Commun."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1109\/MCOM.2015.7263349","article-title":"Non-orthogonal multiple access for 5G: Solutions, challenges, opportunities, and future research trends","volume":"53","author":"Dai","year":"2015","journal-title":"IEEE Commun. Mag."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6425","DOI":"10.1109\/TWC.2015.2453418","article-title":"RF-Based Energy Harvesting in Decode-and-Forward Relaying Systems: Ergodic and Outage Capacities","volume":"14","author":"Gu","year":"2015","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1462","DOI":"10.1109\/LCOMM.2015.2441064","article-title":"Cooperative Non-Orthogonal Multiple Access in 5G Systems","volume":"19","author":"Ding","year":"2015","journal-title":"IEEE Commun. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"102760","DOI":"10.1016\/j.jnca.2020.102760","article-title":"Energy efficient transmission trends towards future green cognitive radio networks (5G): Progress, taxonomy and open challenges","volume":"168","author":"Srivastava","year":"2020","journal-title":"J. Netw. Comput. Appl."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"827","DOI":"10.1109\/COMST.2014.2387697","article-title":"On Green-Energy-Powered Cognitive Radio Networks","volume":"17","author":"Huang","year":"2015","journal-title":"IEEE Commun. Surv. Tutorials"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1109\/LSSC.2018.2827884","article-title":"A 5.8-GHz bidirectional and reconfigurable RF energy harvesting circuit with rectifier and oscillator modes","volume":"1","author":"Dehghani","year":"2018","journal-title":"IEEE-Solid-State Circuits Lett."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2092","DOI":"10.1109\/LCOMM.2018.2863365","article-title":"Performance of Adaptive OMA\/Cooperative-NOMA Scheme With User Selection","volume":"22","author":"Janghel","year":"2018","journal-title":"IEEE Commun. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"937","DOI":"10.1109\/LCOMM.2016.2647250","article-title":"Adaptive Transmission for Cooperative NOMA System With Buffer-Aided Relaying","volume":"21","author":"Luo","year":"2017","journal-title":"IEEE Commun. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2438","DOI":"10.1049\/iet-com.2018.5415","article-title":"Performance analysis of cooperative NOMA with a shared AF relay","volume":"12","author":"Li","year":"2018","journal-title":"IET Commun."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2428","DOI":"10.1109\/LCOMM.2017.2681661","article-title":"Outage Performance for Cooperative NOMA Transmission with an AF Relay","volume":"21","author":"Liang","year":"2017","journal-title":"IEEE Commun. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Ibraheem, S.M., Bedawy, W., Saad, W., and Shokair, M. (2018, January 18\u201319). Outage Performance of NOMA-based DF Relay Sharing Networks over Nakagami-m Fading Channels. Proceedings of the 2018 13th International Conference on Computer Engineering and Systems (ICCES), Cairo, Egypt.","DOI":"10.1109\/ICCES.2018.8639196"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1840","DOI":"10.1049\/iet-com.2018.6075","article-title":"NOMA-based cooperative relaying for secondary transmission in cognitive radio networks","volume":"13","author":"Chu","year":"2019","journal-title":"IET Commun."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"51466","DOI":"10.1109\/ACCESS.2019.2911604","article-title":"Effective resource utilization schemes for decode-and-forward relay networks with NOMA","volume":"7","author":"Duan","year":"2019","journal-title":"IEEE Access"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1109\/LCOMM.2018.2878730","article-title":"Outage Performance of Cooperative Underlay CR-NOMA With Imperfect CSI","volume":"23","author":"Arzykulov","year":"2019","journal-title":"IEEE Commun. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Nauryzbayev, G., Arzykulov, S., Tsiftsis, T.A., and Abdallah, M. (2018, January 20\u201324). Performance of Cooperative Underlay CR-NOMA Networks over Nakagami-m Channels. Proceedings of the 2018 IEEE International Conference on Communications Workshops (ICC Workshops), Kansas City, MO, USA.","DOI":"10.1109\/ICCW.2018.8403605"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Deepan, N., and Rebekka, B. (2019, January 22\u201324). Outage Performance of Full duplex Cooperative NOMA with Energy harvesting over Nakagami-m fading channels. Proceedings of the 2019 TEQIP III Sponsored International Conference on Microwave Integrated Circuits, Photonics and Wireless Networks (IMICPW), Tiruchirappalli, India.","DOI":"10.1109\/IMICPW.2019.8933186"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"89594","DOI":"10.1109\/ACCESS.2019.2926429","article-title":"Joint Spectrum Resource Allocation in NOMA-based Cognitive Radio Network With SWIPT","volume":"7","author":"Song","year":"2019","journal-title":"IEEE Access"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"117308","DOI":"10.1109\/ACCESS.2019.2936321","article-title":"Outage Performance of NOMA in Cooperative Cognitive Radio Networks With SWIPT","volume":"7","author":"Yu","year":"2019","journal-title":"IEEE Access"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Gkonis, P.K., Trakadas, P.T., and Sarakis, L.E. (2020). Non-Orthogonal Multiple Access in Multiuser MIMO Configurations via Code Reuse and Principal Component Analysis. Electronics, 9.","DOI":"10.3390\/electronics9081330"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1218","DOI":"10.1016\/j.future.2017.07.032","article-title":"Throughput analysis of cognitive wireless acoustic sensor networks with energy harvesting","volume":"86","author":"Tang","year":"2018","journal-title":"Future Gener. Comput. Syst."},{"key":"ref_24","first-page":"1","article-title":"Performance Modeling of Communication Networks with Markov Chains","volume":"3","author":"Jeonghoon","year":"2010","journal-title":"Synth. Lect. Data Manag."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1772","DOI":"10.1109\/LCOMM.2012.091712.121395","article-title":"RF energy transfer for cooperative networks: Data relaying or energy harvesting?","volume":"16","author":"Krikidis","year":"2012","journal-title":"IEEE Commun. Lett."},{"key":"ref_26","unstructured":"Gradshteyn, I.S., and Ryzhik, I.M. (2007). Table of Integrals, Series, and Products, Academic Press. [7th ed.]."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2267","DOI":"10.1049\/iet-com.2015.0203","article-title":"Performance analysis of non-orthogonal multiple access in downlink cooperative network","volume":"9","author":"Men","year":"2015","journal-title":"IET Commun."}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/23\/11\/1463\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:26:10Z","timestamp":1760167570000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/23\/11\/1463"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,11,5]]},"references-count":27,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2021,11]]}},"alternative-id":["e23111463"],"URL":"https:\/\/doi.org\/10.3390\/e23111463","relation":{},"ISSN":["1099-4300"],"issn-type":[{"type":"electronic","value":"1099-4300"}],"subject":[],"published":{"date-parts":[[2021,11,5]]}}}