Articles
<![CDATA[Cooperative underlay cognitive radio assisted NOMA: secondary network improvement and outage performance ]]>
<![CDATA[Dinh-Thuan Do]]>;
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Anh-Tu Le]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v17i5.12451
<![CDATA[In this paper, a downlink scenario of a non-orthogonal multiple access (NOMA) scheme with power constraint via spectrum sensing is considered. Such network provides improved outage performance and new scheme of NOMA-based cognitive radio (CR-NOMA) network are introduced. The different power allocation factors are examined subject to performance gap among these secondary NOMA users. To evaluate system performance, the exact outage probability expressions of secondary users are derived. Finally, the dissimilar performance problem in term of secondary users is illustrated via simulation, in which a power allocation scheme and the threshold rates are considered as main impacts of varying system performance. The simulation results show that the performance of CR-NOMA network can be improved significantly.]]>
<![CDATA[Enabling full-duplex in multiple access technique for 5G wireless networks over Rician fading channels ]]>
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Dinh-Thuan Do]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 19, No 1: February 2021 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v19i1.16245
<![CDATA[Nowadays, unmanned aerial vehicle (UAV) relays’assisted Internet of Things (IoT) systems provide facility in order to overcome the large scale fading between source and sink. The full-duplex scheme enables wireless network to provide higher spectrum efficient technology. This paper analyses performance of two users which are served by new emerging non-orthogonal multiple access (NOMA) technique. Exact outage probability of such two users are derived and checked via Monte-Carlo simulation. These analytical results provide guideline to design UAV in real application. This paper provides a comprehensive study to examine impact of interference, fixed power allocation factors to system performance.]]>
<![CDATA[Study on transmission over Nakagami-m fading channel for multiple access scheme without orthogonal signal ]]>
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Dinh-Thuan Do]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 4: August 2020 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v18i4.14227
<![CDATA[In this paper, a downlink performance in non-orthogonal multiple access (NOMA) system is considered. With regard to different priority for two NOMA users, we exploit the closed-form expressions of outage probability over wireless fading channel following Nakagami-m fading. The fixed power allocation factor scheme is examined to reduce the complexity in computation regarding performance analysis. In our analysis, perfect successive interference cancellation (SIC) is applied in order to achieve perfect signal decoding operation. Simulation results show that the considered NOMA downlink scheme is affected by transmit SNR, power allocation factors, fading parameters.]]>
<![CDATA[Wireless power transfer enabled NOMA relay systems: two SIC modes and performance evaluation ]]>
<![CDATA[Dinh-Thuan Do]]>;
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Hong-Nhu Nguyen]]>;
<![CDATA[Tam Nguyen Kieu]]>;
<![CDATA[Si-Phu Le]]>;
<![CDATA[Ngoc-Long Nguyen]]>;
<![CDATA[Nhat-Tien Nguyen]]>;
<![CDATA[Miroslav Voznak]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 6: December 2019 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v17i6.12218
<![CDATA[In this study, we deploy design and performance analysis in new system model using a relaying model, energy harvesting, and non-orthogonal multi-access (NOMA) network. It is called such topology as wireless powered NOMA relaying (WPNR). In the proposed model, NOMA will be investigated in two cases including single successive interference cancellation (SIC) and dual SIC. Moreover, the simultaneous wireless information and power transfer (SWIPT) technology can be employed to feed energy to relays who intend to serve far NOMA users. In particular, exact outage probability expressions are provided to performance evaluation. The results from the simulations are used to demonstrate the outage performance of the proposed model in comparison with the current models and to verify correct of derived expressions.]]>
<![CDATA[Exploiting performance gap among two users in reconfigurable intelligent surfaces-aided wireless systems ]]>
<![CDATA[Dinh-Thuan Do]]>;
<![CDATA[Chi-Bao Le]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 20, No 1: February 2022 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v20i1.19001
<![CDATA[In this work, we study the outage performance of a reconfigurable intelligent surfaces (RIS)-aided wireless systems in the presence of non-orthogonal multiple access (NOMA). In particular, different power factors are allocated to users which belong a dedicated group. We derive exact outage probability of two users in a group. Specifically, it is assumed that the RIS is placed between the source and the users and far user has better performance under assistance of RIS. We also provide comparison analysis to investigate the effect of the main parameters on the outage performance of our proposed system, such as the number of tunable elements of the RIS, power allocation factors, target rates and the average signal-to-noise ratio at the base station. If we set small tunable elements for RIS, we can obtain the best performance. By using MonteCarlo simulation, we verify our analytical results via simulations. Our main results reported in this paper show the positive effect once we deploy RISs for guaranteeing fairness among NOMA users in wireless systems.]]>
<![CDATA[Exploiting Outage Performance of Wireless Powered NOMA ]]>
<![CDATA[Dinh-Thuan Do]]>;
<![CDATA[Chi-Bao Le]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 5: October 2018 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v16i5.9385
<![CDATA[Considering a dual-hop energy-harvesting (EH) non-orthogonal multiple access (NOMA) relaying system, this paper considers novel relaying protocol based on time power switching-based relaying (TPSR) and power switching-based relaying (PSR) schemes for two kinds of gain factors regarding amplify-and-forward mode. We introduce novel system model relaying network with impacts of energy harvesting fractions and derive analytical expressions for outage probability for the information transmission link. It confirmed that right selection of power allocation for NOMA to obtain optimal performance as compared study in two considered schemes. We also explore impacts of other key parameters of system to outage performance evaluation for different channel models. Simulation results are presented to corroborate the proposed methodology.]]>
<![CDATA[Study on outage performance gap of two destinations on CR-NOMA network ]]>
<![CDATA[Hong-Nhu Nguyen]]>;
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Nhat-Tien Nguyen]]>;
<![CDATA[Dinh-Thuan Do]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 1: February 2020 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v18i1.13271
<![CDATA[Non-orthogonal multiple access (NOMA) and cognitive radio (CR) are promising for solving the severe spectral scarcity problem encountered by the next generation of wireless communication systems. This study aims to improve spectral efficiency at two secondary destinations by investigating a CR-NOMA network under situation of the perfect successive interference cancellation (SIC). We also derive the exact outage probability for secondary users. Furthermore, an approximate computation method is applied to indicate more insights. It is confirmed that the performance achieved together with performance gap among two users can be obtained due to different power allocation factors assigned to users.]]>
<![CDATA[Ergodic capacity computation in cognitive radio aided non-orthogonal multiple access systems ]]>
<![CDATA[Dinh-Thuan Do]]>;
<![CDATA[Chi-Bao Le]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 11, No 1: February 2022 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v11i1.3297
<![CDATA[In this article, the performance of cognitive radio system benefits from non-orthogonal multiple access (NOMA) scheme. We then examine system metrics to adjust its quality of signal processing. We focus on performance of the secondary network containing NOMA users which have some impacts from normal user and primary nodes. We refer to enhancement of the fairness and spectrum utilization by enabling spectrum sharing. In particular, the NOMA power allocation factors are assigned to provide different ergodic capacities for two NOMA users in the downlink of such cognitive radio-non-orthogonal multiple access (CR-NOMA) system. This article presents approximated ergodic capacity of secondary users, in which this system adopts the Rayleigh fading. The closed-form expressions are expected to match with Monte-Carklo simulation results and main system parameters can be determined to control performance of such CR-NOMA. Finally, this system is prominent once its performance outperforms than that of conventional orthogonal multiple access (OMA)-based system.]]>
<![CDATA[Secure outage probability of cognitive radio network relying non-orthogonal multiple access scheme ]]>
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Dinh-Thuan Do]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 10, No 2: April 2021 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v10i2.2116
<![CDATA[This paper studies the secondary network relying relay selection to transmit signal from the secondary source (base station) to two destinations. Especially, two destinations are required non-orthogonal multiple access (NOMA) scheme and it benefits to implementation of the Internet of Things (IoT) systems. However, eavesdropper over-hears signal related link from selected relay to destination. This paper measure secure performance via metric, namely secure outage probability (SOP). In particular, signal to noise ratio (SNR) criterion is used to evalute SOP to provide reliable transmission to the terminal node. Main results indicates that the considered scheme provides performance gap among two signals at destination. The exactness of derived expressions is confirmed via numerical simulation.]]>
<![CDATA[Studying strictly positive secure capacity in cognitive radio-based non-orthogonal multiple access ]]>
<![CDATA[Chi-Bao Le]]>;
<![CDATA[Dinh-Thuan Do]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 10, No 2: April 2021 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v10i2.2117
<![CDATA[This paper studies a downlink security-aware secure outage performance in the secondary network of cognitive radio-assisted non-orthogonal multiple access network (CR-NOMA). The multiple relay is employed to assist transmission from the secondary source to destinations. The security-aware performance is subject to constraints in fixed power allocation factor assigned to each secondary user. The security-aware secure performance is based on channel state information (CSI) at the physical layer in which an eavesdropper intends to steal information. According to the considered system, exact expressions of Strictly positive secure capacity (SPSC) are proved to analyze system in terms of secure performance. Finally, the secondary user secure problem is evaluated via Monte-Carlo simulation method. The main results indicate that the secure performance of proposed system can be improved significantly.]]>
