arXiv subjects

Oğuz Kucur

Publications and source records attributed to Oğuz Kucur.

8 recordsLinked to original sources

arXiv2026

Secrecy Performance of an Artificial Noise Aided Dual-Hop SWIPT MIMO-NOMA Network in Presence of Practical Impairments

This paper investigates the secrecy performance of a cooperative non-orthogonal multiple access (NOMA) network under practical impairments. In the considered system, the source employs orthogonal space-time block coding (OSTBC) transmission, legitimate users adopt receive antenna selection (RAS), and the eavesdropper utilizes maximal-ratio combining (MRC) scheme. Moreover, an energy-constrained amplify-and-forward relay harvests energy from the received signal and allocates the harvested energy to information forwarding and artificial noise (AN) generation. To capture the realistic performance of a more practical transmission scenario, channel estimation errors (CEE), feedback delay (FBD), imperfect successive interference cancellation (SIC), and imperfect AN cancellation are taken into account. For this system, closed-form expressions for the legitimate-user signal-to-interference+noise ratios (SINR) cumulative distribution function (CDF) and the eavesdropper SINR probability density function (PDF) are derived, and a tractable analytical secrecy outage probability (SOP) expressions are obtained. In addition, the high-SNR secrecy behavior is characterized under ideal channel state information (CSI) conditions and practical impairments, revealing the achievable secrecy diversity order and the secrecy outage floor, respectively. Moreover, secrecy throughput and energy efficiency are analyzed based on the obtained SOP results. The numerical findings are in close agreement with the analytical results and further illustrate how the secrecy behavior of the proposed system is affected by key design parameters and practical impairments. The obtained results indicate that transmit and receive diversity and proper AN power allocation significantly improve the secrecy performance, whereas practical impairments lead to non-zero SOP floors in the high signal-to-noise ratio region.

eess.SP↗

arXiv2026

Performance of DF Multihop Networks with TAS/GSC over Nakagami-m Fading Channels

In this work, transmit antenna selection (TAS) and generalized selection combining (GSC), i.e., TAS/GSC is revised over independent identically distributed Nakagami-$m$ flat fading channels with pretty simple newly derived closed-form expressions of outage probability (OP), symbol error rate (SER), and ergodic capacity. While compares to their multinomial theorem-based counterparts for GSC and TAS/GSC, the intelligibility, practicality, and simplicity of our derivations are invaluable, which from now on facilitates TAS/GSC implementations in various fields. As an example, performance analysis of decode-and-forward multihop networks with TAS/GSC implementation in each hop is presented over independent non-identically distributed Nakagami-$m$ fading channels in this work, with the closed-form expressions for OP, SER, and ergodic capacity. Finally, all derived analytical expressions are validated via Monte-Carlo simulation technique.

eess.SP↗

arXiv2024

Performance of User-Assisted Nonlinear Energy Harvesting NOMA Network with Alamouti/MRC

This paper focuses on evaluating the outage performance of a dual-hop single-phase non-orthogonal multiple-access (NOMA) system. The base station employs the Alamouti space-time block coding technique (Alamouti-STBC), enabling simultaneous communication with two mobile users, and the far user employs a maximal ratio combining (MRC) scheme. In this setup, the near user serves as a full-duplex (FD) (or half-duplex (HD)) energy harvesting (EH) relay, adopting decode-and-forward (DF) protocol for the far user. The study involves the development of a system model and the closed-form equations of exact and asymptotic outage probabilities (OP) over Nakagami-m fading channels with and without direct link considering a threshold-based nonlinear EH relaying model. We verify analytical results by Monte Carlo simulations and show that the presence of a direct link in the system enhances the performance of the far user considerably by mitigating the degradation caused by the self-interference in the near user.

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arXiv2021

Relay Selection with Imperfect SIC for FD/HD NOMA Cooperative Networks over Nakagami-$m$ Fades

In this work, a non-orthogonal multiple access (NOMA) based transmission between two sources and two end-users is examined over independent non-identically distributed (i.n.i.d.) slow Nakagami-$m$ fading channels, where a single relay using decode-and-forward (DF) protocol is selected out of a set of full-duplex/half-duplex (FD/HD) multiple relays in accordance with the quality of service criterion. Two relay selection (RS) strategies, selecting a relay to maximize data rate of user 1 at selected relay and selecting a relay out of a set of relays providing service quality for user 1 to maximize data rate of user 2, are analyzed. Additionally, not only perfect successive interference cancellation (pSIC) but also imperfect SIC (ipSIC) is considered. The exact and asymptotic outage probability (OP) expressions are derived and validated via Monte Carlo simulation technique. Unlike existing works, our expressions are unique and valid for all cases such as FD and HD together with pSIC and ipSIC, i.e. expressions are not given separately but in a single compact form. Effect of each component such as pSIC, ipSIC, and self-interference (SI) for FD transmission on error floor of OP is demonstrated. Moreover, the optimum relay location is illustrated for a plenty of scenarios consisting of combination of different power allocations, data rates, pSIC/ipSIC, and total transmitted powers.

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arXiv2019

Majority Based TAS/MRC Scheme in Downlink NOMA Network with Channel Estimation Errors and Feedback Delay

The antenna selection (AS) in non-orthogonal multiple access (NOMA) networks is still a challenging problem since finding optimal AS solution may not be available for all channel realizations and has quite computational complexity when it exists. For this reason, in this paper, we develop a new suboptimal solution, majority based transmit antenna selection (TAS-maj), with significant reduction in computational complexity. The TAS-maj basically selects the transmit antenna with the majority. It is more efficient when compared to previously proposed suboptimal AS algorithms, namely max-max-max (A^3) and max-min-max (AIA) because these schemes are merely interested in optimizing the performance of the strongest and weakest users, respectively at the price of worse performance for the remaining users. On the other hand, the TAS-maj scheme yields better performance for more than half of mobile users in the NOMA networks. In this paper, we consider a multiple-input multiple-output communication system, where all the nodes are equipped with multi-antenna. Besides the TAS-maj is employed at the base station, a maximal ratio combining (MRC) is also employed at each mobile user in order to achieve superior performance. The impact of the channel estimation errors (CEEs) and feedback delay (FD) on the performance of the TAS-maj/MRC scheme is studied in the NOMA network over Nakagami-m fading channels.

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arXiv2019

Performance of Cooperative NOMA with MRT/RAS in Nakagami-m Fading Channels with Channel Estimation Errors

This paper studies the performance of a downlink non-orthogonal multiple access (NOMA) based cooperative network with maximal ratio transmission/receive antenna selection (MRT/RAS) over Nakagami-m fading channels in the presence of channel estimation errors (CEEs). In the system, a base station communicates with multiple mobile users through a half duplex channel state information based amplify-and-forward relay. All nodes are equipped with multiple antennas and the hybrid diversity technique MRT/RAS is employed in both hops. The outage behavior of the system is investigated by driving closed-form expression for outage probability (OP). In addition, the corresponding lower and upper bounds of the derived OP are obtained. Moreover, the behavior of the system is studied in high signal-to-noise ratio region by obtaining an error floor value in the presence of CEE as well as achieving diversity and array gains in the absence of CEE. Finally, the analytical results in the presence and absence of the CEEs are verified by the Monte Carlo simulations. Results show that the MRT/RAS scheme enhances the OP significantly and is much more robust to the CEEs in comparison with the single antenna case.

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arXiv2012

On the Performance of Transmit Antenna Selection Based on Shadowing Side Information

In this paper, a transmit antenna selection scheme, which is based on shadowing side information, is investigated. In this scheme, the selected single transmit antenna provides the highest shadowing coefficient between transmitter and receiver. By the proposed technique, the frequency of the usage of the feedback channel from the receiver to the transmitter and also channel estimation complexity at the receiver can be reduced. We study the performance of our proposed technique and in the analysis, we consider an independent but not identically distributed Generalized-K composite fading model. More specifically exact and closed-form expressions for the outage probability, the moment generating function, the moments of signal-to-noise ratio, and the average symbol error probability are derived. In addition, asymptotic outage probability and symbol error probability expressions are also presented in order to investigate the diversity order and the array gain. Finally, our theoretical performance results are validated by Monte Carlo simulations.

cs.IT↗

arXiv2012

New Results on the Sum of Gamma Random Variates With Application to the Performance of Wireless Communication Systems over Nakagami-m Fading Channels

The probability density function (PDF) and cumulative distribution function of the sum of L independent but not necessarily identically distributed Gamma variates, applicable to the output statistics of maximal ratio combining (MRC) receiver operating over Nakagami-m fading channels or in other words to the statistical analysis of the scenario where the sum of squared Nakagami-m distributions are user-of-interest, is presented in closed-form in terms of well-known Meijer's G function and easily computable Fox's H-bar function for integer valued and non-integer valued m fading parameters. Further analysis, particularly on bit error rate via a PDF-based approach is also offered in closed form in terms of Meijer's G function and Fox's H-bar function for integer valued fading parameters, and extended Fox's H-bar function (H-hat) for non-integer valued fading parameters. Our proposed results complement previous known results that are either expressed in terms of infinite sums, nested sums, or higher order derivatives of the fading parameter m.

cs.IT↗