Fatma BARDAK, Mustafa NAMDAR, Arif BAŞGÜMÜŞ

RÖLE YARDIMLI AŞAĞI YÖNLÜ NOMA SİSTEMLERİNİN BİLİŞSEL RADYO AĞLARDAKİ ERGODİK KAPASİTE ANALİZİ

Bu çalışmada, röle yardımlı aşağı yönlü dikgen olmayan çoklu erişim (NOMA) sistemlerinin bilişsel radyo ağlardaki ergodik kapasite analizi incelenmektedir. Önerilen sistem modelindeki matematiksel çıkarımlar, ikincil ağdaki yakın ve uzak kullanıcılar için tam ve yaklaşık ergodik kapasite kapalı form denklemlerinin üstel dağılımlı kanal göz önüne alınarak türetilmesiyle elde edilmektedir. Hem rölede, hem de yakın ve uzak kullanıcılarda ardışık girişim iptali gerçekleşmesi durumunda, toplam ergodik kapasite performansı düğümler arası mesafe, güç paylaşım katsayısı, iletim gücü ve yol kaybı üssü parametreleri dikkate alınarak, 〖10〗^6 tekrarlı Monte Carlo benzetimleriyle analiz edilmektedir. Elde edilen nümerik sonuçlar, yakın kullanıcıya atanan güç tahsisinin artması ile ergodik toplam kapasitenin arttığını göstermektedir. Birincil ağ vericisinin röleden uzaklaşmasının sistem performansını iyileştirdiği de gözlenmiştir. Yakın kullanıcı için tam olarak hesaplanan ergodik toplam kapasite başarımının, yaklaşık olarak hesaplanan ergodik toplam kapasite performansı ile örtüşmesi, ancak yüksek işaret gürültü oranı (SNR) bölgesinde mümkün olmaktadır. Bu durum, ikincil ağ olarak kurgulanan aşağı yönlü NOMA sisteminin, ortak kanal girişimi olarak etki gösteren birincil ağ ile aynı frekans bandını kullanmasının etkisi olarak değerlendirilmiştir.

Anahtar Kelimeler:

Aşağı Yönlü NOMA, Bilişsel Radyo, Ergodik Kapasite, Röle Ağlar

ERGODIC CAPACITY ANALYSIS OF THE RELAY ASSISTED DOWNLINK NOMA SYSTEMS IN COGNITIVE RADIO NETWORKS

this study, the ergodic capacity analysis of the relay assisted downlink non-orthogonal multiple access (NOMA) systems in cognitive radio networks is investigated. Mathematical inferences in the proposed system model are obtained by deriving the closed-form equations of the exact and approximate ergodic capacities for the far and near users in the secondary network by considering exponentially distributed channels. In case of successive interference cancellation is implemented in both relay, far and near users, the ergodic sum capacity performances are analyzed with 〖10〗^6 repeated Monte Carlo simulations, considering the distance between nodes, power allocation coefficient, transmission power, and path loss coefficient parameters. The numerical results show that the ergodic total capacity increases with the increase in power allocation assigned to the near user. It has also been observed that moving the primary network transmitter away from the relay improves the system performance. The exact calculation of the ergodic total capacity performance for the near user is only possible in the high signal-to-noise ratio (SNR) region to coincide with the approximately calculated ergodic total capacity performance. This situation is evaluated as the effect of the downlink NOMA system designed as a secondary network using the same frequency band as the primary network acting as a co-channel interference.

Keywords:

Downlink NOMA, Cognitive Radio, Ergodic Capacity, Relay Networks,

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Arzykulov S., Tsiftsis T. A., Nauryzbayev G., and Abdallah M., 2019. Outage Performance of Cooperative Underlay CR-NOMA with Imperfect CSI. IEEE Communications Letters, 23(1), 176-179.
Arzykulov S., Nauryzbayev G., Tsiftsis T. A., Maham B., and Abdallah M., 2019. On the Outage of Underlay CR-NOMA Networks with Detect-and-Forward Relaying. IEEE Transactions on Cognitive Communications and Networking, 5(3), 795-804.
Bardak, F. K., Namdar, M., and Basgumus, A., 2020. Performance Analysis of NOMA Systems in Relay-Assisted Cognitive Radio Networks. IEEE Signal Processing and Communications Applications Conference (SIU), 1-4.
Dai L., Wang B., Yuan Y., Han S., Chih-Lin I., and Wang Z., 2015. Non-Orthogonal Multiple Access for 5G: Solutions, Challenges, Opportunities, and Future Research Trends. IEEE Communications Magazine, 53(9), 74-81.
Dai L., Wang B., Ding Z., Wang Z., Chen S., and Hanzo L., 2018. A Survey of Non-Orthogonal Multiple Access for 5G. IEEE Communications Surveys & Tutorials, 20(3), 2294-2323.
Ding Z., Lei X., Karagiannidis G. K., Schober R., Yuan L., and Bhargava V., 2020. A Survey of NOMA: Current Status and Open Research Challenges. IEEE Journal on Selected Areas in Communications, 35(10), 2181-2195.
Gradshteyn I. S., and Ryzhik I. M., 2007. Table of integrals, series and products, 7th edn. New York: Academic Press.
Guo H., Ge J., and Ding H., 2011. Symbol Error Probability of Two-Way Amplify-and-Forward Relaying. IEEE Communications Letter, 15(1), 22-24.
Haykin S., 2005. Cognitive Radio: Brain-empowered Wireless Communications. IEEE Journal on Selected Areas in Communications, 23(21), 201-220.
Ho C. Y., Leow C. Y., 2019. Cooperative Non-Orthogonal Multiple Access with Physical Layer Network Coding. IEEE Access, vol. 7, 44894-44902.
Im G., Lee J. H., 2019. Outage Probability for Cooperative NOMA Systems with Imperfect SIC in Cognitive Radio Networks. IEEE Communications Letters, 23(4), 692-695.
Kader M. F., Shahab M. B., and Shin S. Y., 2017. Exploiting Non-orthogonal Multiple Access in Cooperative Relay Sharing. IEEE Communications Letters, 21(5), 1159-1162.
Kim J. B., and Lee I. H., 2015. Non-Orthogonal Multiple Access in Coordinated Direct and Relay Transmission. IEEE Communications Letters, 19(11), 2037-2040.
Liu Y., Ding Z., Elkashlan M., Yuan L., 2016. Non-orthogonal Multiple Access in Large-Scale Underlay Cognitive Radio Networks. IEEE Transactions on Vehicular Technology, 65(12), 10152-10157.
Lv L., Chen L., Ni Q., Ding Z., and Liang H. 2018. Cognitive Non-Orthogonal Multiple Access with Cooperative Relaying: A New Wireless Frontier for 5G Spectrum Sharing. IEEE Communications Magazine, 56(4), 188-195.
Mohammadi M., Chalise B. K., Hakimi A., Mobini Z., Suraweera H. A., and Ding Z., 2018. Beamforming Design and Power Allocation for Full-Duplex Non-Orthogonal Multiple Access Cognitive Relaying. IEEE Transactions on Communications, 66(12), 5952-5965.
Namdar M., Ilhan H., 2018. Exact Closed-Form Solution for Detection Probability in Cognitive Radio Networks with Switch-and-Examine Combining Diversity, IEEE Transactions on Vehicular Technology, 67(9), 8215-8222.
Sun Q., Han S., Chin-Lin I., and Pan Z., 2015. On the Ergodic Capacity of MIMO NOMA Systems. IEEE Wireless Communications Letters, 4(4), 405-408.
Ucar-Gul M., Namdar M., and Basgumus A., 2020. Performance Analysis of Two-Way AF Relaying System with the Presence of Hardware Impairments over Nakagami-m Fading Channels. IET Communications, 14(15), 2618-2627.
Wang H., Lee J., Kim S., and Hong D., 2010. Capacity Enhancement of Secondary Links through Spatial Diversity in Spectrum Sharing. IEEE Transactions on Wireless Communications, 9(2), 494-499.
Wang X., Wang J., He L., and Song J., 2018. Outage Analysis for Downlink NOMA with Statistical Channel State Information. IEEE Wireless Communications Letters, 7(2), 142-145.
Wu W. C., 2019. A novel Code-aided non-orthogonal multiple access in downlink multiuser MIMO System. IEEE International Conference of Intelligent Applied Systems on Engineering (ICIASE), 251-154.
Yue X., Liu Y., Kang S., Nallanathan A., Chen Y., 2018. Modeling and Analysis of Two-Way Relay Non-Orthogonal Multiple Access Systems. IEEE Transactions on Communications, 66(9), 3784-3796.
Zhang C., Ge J., Li J., Rui Y., and Guizani M., 2015. A Unified Approach for Calculating the Outage Performance of Two-Way AF Relaying Over Fading Channels. IEEE Transactions on Vehicular Technology, 64(3), 1218-1229.
Zhong C., Zhang Z., 2016. Non-Orthogonal Multiple Access With Cooperative Full-Duplex Relaying. IEEE Communications Letters, 20(12), 2478-2481.