Erküçük, Serhat
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Erküçük, Serhat
S.,Erküçük
S. Erküçük
Serhat, Erküçük
Erkucuk, Serhat
S.,Erkucuk
S. Erkucuk
Serhat, Erkucuk
Erküçük, S.
Erküçük,S.
Erküçük, Serhat
S.,Erküçük
S. Erküçük
Serhat, Erküçük
Erkucuk, Serhat
S.,Erkucuk
S. Erkucuk
Serhat, Erkucuk
Erküçük, S.
Erküçük,S.
Erküçük, Serhat
Job Title
Prof. Dr.
Email Address
Main Affiliation
Electrical-Electronics Engineering
Electrical-Electronics Engineering
05. Faculty of Engineering and Natural Sciences
01. Kadir Has University
Electrical-Electronics Engineering
05. Faculty of Engineering and Natural Sciences
01. Kadir Has University
Status
Former Staff
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
17
PARTNERSHIPS FOR THE GOALS
0
Research Products
14
LIFE BELOW WATER
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
0
Research Products
15
LIFE ON LAND
0
Research Products
1
NO POVERTY
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
4
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
2
ZERO HUNGER
0
Research Products
4
QUALITY EDUCATION
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
13
CLIMATE ACTION
0
Research Products
5
GENDER EQUALITY
0
Research Products
This researcher does not have a Scopus ID.
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Scholarly Output
66
Articles
20
Views / Downloads
385/6752
Supervised MSc Theses
9
Supervised PhD Theses
0
WoS Citation Count
304
Scopus Citation Count
408
WoS h-index
11
Scopus h-index
12
Patents
0
Projects
0
WoS Citations per Publication
4.61
Scopus Citations per Publication
6.18
Open Access Source
36
Supervised Theses
9
| Journal | Count |
|---|---|
| IEEE Transactions on Wireless Communications | 4 |
| IET Communications | 3 |
| IEEE Transactions on Vehicular Technology | 3 |
| 2011 IEEE International Conference on Ultra-Wideband (ICUWB) | 2 |
| International Journal of Communication Systems | 2 |
Current Page: 1 / 7
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Competency Cloud
66 results
Scholarly Output Search Results
Now showing 1 - 10 of 66
Master Thesis SCMA codebook design approaches(Kadir Has Üniversitesi, 2020) Kiracı, Furkan; Erküçük, SerhatIn 4G systems, Orthogonal Frequency-Division Multiple Access (OFDMA) has been used conventionally for multiple access purposes. This technique has low spectral efficiency since it allocates the resources orthogonally to each user. As an alternative to this technique, Non-orthogonal Multiple Access (NOMA) has been proposed for new generation 5G systems as it allows different users to use the same resources and therefore, increases spectral efficiency. Sparse Code Multiple Access (SCMA) is a code-based NOMA technique and its performance depends on codebook design. In this thesis, four different approaches are proposed by examining the design of the conventional codebook, which is widely used in SCMA studies in the literature. In the first approach, the distances between the constellation set points have been increased while the total energy remains constant. In the second approach, the angle between the constellation set points on the sub-carriers in the codebook has been equally set. In the third approach, by applying the permutation method, it has been aimed to reduce the complexity in the codebook by multiplying the constellation set points on the first and second sub-carriers with the halfangle formula. In the fourth approach, a new constellation set points with the energy remaining constant has been designed. Considering the four different design approaches, the conventional codebook has been modified. Simulation results have shown that 1-2dB gain can be achieved using different design approaches in the high signal-to-noise-ratio (SNR) region.Book Part Citation - Scopus: 1Effect of Inter-Block Region on Compressed Sensing Based Channel Estimation in Tds-Ofdm Systems(Institute of Electrical and Electronics Engineers Inc., 2016) Başaran, Mehmet; Erküçük, Serhat; Şenol, Habib; Çırpan, Hakan AliTime domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) is the basis technology for digital television standard (DTV) employed in some countries thanks to its high spectral efficiency when compared to traditional cyclic prefix OFDM. Moreover, it does not require pilot usage in frequency domain channel estimation. Instead of data usage as cyclic prefix, pseudo-noise (PN) sequences are transmitted in guard intervals. Due to interference from the previous OFDM data symbol, the received signal in guard interval can be decomposed into a small-sized signal that contains only PN sequences utilizing the inter-block-interference (IBI)-free region in the convolution matrix. Due to sparsity, multipath fading channel can be obtained by the application of compressed sensing (CS) technique to reconstruct the high-dimensional sparse channel from the decreased-size of received signal through the known PN sequence matrix. In this study, the effect of the size of IBI-free region on CS and Bayesian CS (BCS) based channel estimation is investigated. Accordingly, reconstruction error performances of basis pursuit (BP) and BCS are compared. Simulation results show that the channel estimation can be improved by trading-off the length of the IBI-free region. However, an increase in IBI-free region leads to decreased energy efficiency at both the transmitter and receiver side.Master Thesis Primary User Detection in Ultrawide-Band Based Wireless Sensor Networks(Kadir Has Üniversitesi, 2013) Sabucu, Yağmur; Erküçük, SerhatIn this thesis ultra-wideband (UWB) based wireless sensor networks (WSNs) are considered for the detection of a primary user. Different from earlier works (i) both uplink and downlink information of the primary user are assessed for the primary user detection and (ii) iEEE 802.15.4a standard is considered for the implementation of each secondary user. Specifically the worked focused on the comparison of the two iEEE 802.15.4a based signalling namely binary pulse position modulation (BPPM) and combined BPPM/ binary phase shift keying (BPPM/BPSK) and the implementation of noncoherent receivers at the fusion center for reduced complexity. Accordingly the sensor-fusion center link is investigated in detail considering practical implementation conditions. Some suggestions have been provided based on the primary user detection performance results of the UWB based WSNs. -- Abstract'tan.Article Citation - WoS: 23Citation - Scopus: 30Sparse Code Multiple Access-Based Edge Computing for Iot Systems(IEEE-Inst Electrical Electronics Engineers Inc, 2019) Alnoman, Ali; Erküçük, Serhat; Anpalagan, AlaganIn this paper, a sparse code multiple access (SCMA)-based edge computing scheme is proposed for Internet-of- Things (IoT) systems. The aim of implementing SCMA, which is a nonorthogonal multiple access resource allocation technique, is to improve network connectivity and maximize data rate provision. The proposed edge-IoT system is investigated under different SCMA configurations to explore the various performance aspects such as connectivity, throughput, task completion time, and complexity. First, the problem is formulated as a data rate maximization problem for SCMA-based heterogeneous networks under power constraints. Then, the problem is subdivided into a power allocation problem, which is solved using the water filling approach, and a codebook allocation problem that is solved using a heuristic algorithm. The results show that the SCMA scheme can significantly improve the IoT performance compared to the conventional orthogonal frequencydivision multiple access resource allocation scheme in terms of connectivity, throughput, and task completion time provided that SCMA configurations are suitable with IoT processing capabilities to avoid undesired detection latency.Article Citation - WoS: 23Citation - Scopus: 31Energy Efcient Downlink Resource Allocation in Cellular Iot Supported H-Crans(Institute of Electrical and Electronics Engineers Inc., 2021) Ferdouse, Lilatul; Woungang, Isaac W.; Anpalagan, Alagan S.; Erküçük, SerhatThe cloud computing supported heterogeneous cloud radio access network (H-CRAN) is one of the promising solutions to support cellular IoT devices with the legacy cellular systems. However, the dense deployment of small cells with fractional frequency reuse in orthogonal frequency division multiple access (OFDMA) based H-CRANs increases intra- and inter-cell interference, turning the resource allocation into a more challenging problem. In general, the macro cell users are considered as the legacy users, whereas the cellular IoT devices and small cell users share the macro cell users resource blocks in an underlaid approach. In this paper, we investigate an underlaid approach of resource allocation for small and macro cell users to improve the energy efficiency (EE) in H-CRANs. The solution approaches are derived with the Dinkelbach, Lagrange and Alternating Direction Method of Multipliers (ADMM) methods by considering maximum power, resource block allocation, fronthaul capacity and quality of service (QoS) constraints of macro cell users. A two-step energy efficient underlaid cellular IoT (UCIoT) supported H-CRAN method is proposed and evaluated with overlaid cellular IoT (OC-IoT) supported H-CRAN and underlaid H-CRAN without cellular IoT devices. The proposed method is evaluated in terms of energy efficiency and the Jain's fairness index, considering the effect of number of cellular IoT density in each small cell of the H-CRAN. The simulation results demonstrate the effectiveness of the proposed approach compared to earlier approaches.Conference Object Citation - WoS: 22Citation - Scopus: 32Physical-Layer Security in Visible Light Communications(Institute of Electrical and Electronics Engineers Inc., 2020) Yeşilkaya, Anıl; Çoğalan, Tezcan; Erküçük, Serhat; Şadi, Yalçın; Panayırcı, Erdal; Haas, Harald; Poor, Harold VincentOptical wireless communications (OWC) and its potential to solve physical layer security (PLS) issues are becoming important research areas in 6G communications systems. In this paper, an overview of PLS in visible light communications (VLC), is presented. Then, two new PLS techniques based on generalized space shift keying (GSSK) modulation with spatial constellation design (SCD) and non-orthogonal multiple access (NOMA) cooperative relaying are introduced. In the first technique, the PLS of the system is enhanced by the appropriate selection of a precoding matrix for randomly activated light emitting diodes (LEDs). With the aid of a legitimate user's (Bob's) channel state information (CSI) at the transmitter (CSIT), the bit error ratio (BER) of Bob is minimized while the BER performance of the potential eavesdroppers (Eves) is significantly degraded. In the second technique, superposition coding with uniform signaling is used at the transmitter and relays. The design of secure beamforming vectors at the relay nodes along with NOMA techniques is used to enhance PLS in a VLC system. Insights gained from the improved security levels of the proposed techniques are used to discuss how PLS can be further improved in future generation communication systems by using VLC.Conference Object Citation - WoS: 1Busy Tone Based Power Control for Coordination of Iffy 802.11af and 802.22 System(IEEE, 2017) Ülgen, Oğuz; Erküçük, Serhat; Karatalay, Onur; Baykas, TuncerIn this paper, a new power control algorithm based on busy tone approach has been proposed for the coordination of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier studies, in addition to both 802.11af access point and clients listening to the busy tone, they also adjust their communication power according to the location information and use hopping for communication, if needed Acccordingly, interference caused to 802.22 systems has been reduced while the 802.11af systems are still able to communicate. This study quantifies the 802.11af and 802.22 system performances in terms of interfering packet rate and succesful packet transmission rate for different scenarios considering the communication parameters and channel models adapted for the standards.Conference Object Citation - WoS: 11Citation - Scopus: 13Flexible Physical Layer Based Resource Allocation for Machine Type Communications Towards 6g(Institute of Electrical and Electronics Engineers Inc., 2020) Şadi, Yalçın; Erküçük, Serhat; Panayırcı, ErdalThe exponential growth of Internet of Things applications necessitates the design of next generation cellular systems to provide native support for machine type communications (MTC). While 5G aims at providing this native support under domain of massive MTC (mMTC) as one of the three major domains it focuses; i.e., enhanced mobile broadband, ultra reliable low latency communication, and mMTC, the enabling technologies and communication architectures are still limited and incomplete considering the nearly standardized efforts under 3GPP Releases 15 and 16. Studies towards 6G should elaborate on enabling truly massive MTC flexibly to support fast growing machine-to-machine (M2M) services with massive number of devices and very diverse quality of service (QoS) requirements. In this paper, we study radio resource allocation for mMTC based on the envisioned flexible physical layer architecture for 5G and beyond, possibly including 6G. We first present an overview of the 5G New Radio physical layer aspects particularly focusing on multiple numerologies and discuss the 3GPP features in Releases 15-17 as possible enablers of a flexible radio resource allocation scheme. Then, we propose a polynomial-time persistent resource allocation scheme for M2M communications aiming at meeting diverse QoS requirements of the M2M applications while achieving spectral efficiency. Finally, we present some numerical results and discuss future research directions for access schemes to enable truly massive MTC.Article A Comparative Analysis of Diversity Combining Techniques for Repetitive Transmissions in Time Spreading Scma Systems(John Wiley & Sons Ltd, 2024) Ulgen, Oguz; Tufekci, Tolga Kagan; Sadi, Yalcin; Erkucuk, Serhat; Anpalagan, Alagan; Baykas, TuncerSparse Code Multiple Access (SCMA) is a recently introduced wireless communication network technology. There are various techniques in SCMA systems to increase the system's efficiency, and one of these techniques is time spreading. By adding repetitive transmission and time spreading into SCMA, it is shown in previous works that the Bit-Error-Rate (BER) results are improved convincingly. However, in the previous works, other diversity combining techniques have not been considered. This paper introduces a new approach to further improve the performance of repetitive transmission in SCMA systems with time spreading by adding imperialist competitive algorithm in diversity combining. Alongside, four different combining techniques; equal gain combining, maximal ratio combining, selection combining, and genetic algorithm are considered to bring comparative analysis to show the significance of the new technique. Results show that the proposed method offers up to 2.3 dB gain in terms of BER, under certain conditions.Article Citation - WoS: 14Citation - Scopus: 19Channel Estimation for Tds-Ofdm Systems in Rapidly Time-Varying Mobile Channels(IEEE-Inst Electrical Electronics Engineers Inc, 2018) Başaran, Mehmet; Şenol, Habib; Erküçük, Serhat; Çırpan, Hakan AliThis paper explores the performance of time-domain synchronous orthogonal frequency-division multiplexing (TDS-OFDM) systems operated under rapidly time-varying mobile channels. Since a rapidly time-varying channel contains more unknown channel coefficients than the number of observations, the mobile channel can conveniently be modeled with the discrete Legendre polynomial basis expansion model to reduce the number of unknowns. The linear minimum mean square error (LMMSE) estimate can be exploited for channel estimation on inter-block-interference-free received signal samples owing to transmitting pseudo-noise (PN) sequences. In conventional TDS-OFDM systems, the channel estimation performance is limited due to estimating channel responses only from the beginning part of the channel. Therefore, a new system model named "partitioned TDS-OFDM system" is proposed to improve the system performance by inserting multiple PN sequences to the middle and end parts of the channel as well. In addition to providing the reconstruction error performance, Bayesian Cramer-Rao lower hound is derived analytically. Also, the LMMSE-based symbol detection is employed. To alleviate the negative effects of inter-carrier-interference (ICI) occuring in mobile channels, ICI cancellation is applied to enhance the detection performance. The simulation results demonstrate that the proposed TDS-OFDM system is superior to the conventional system and its corresponding performance is able to approach the achievable lower performance bound.
