Erdal Panayırcı

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Panayırcı, Erdal

Name Variants

P., Erdal
Panayirci,E.
Panayirci,Erdal
Erdal Panayırcı
Panayirci E.
Panayırcı,E.
Panayirci, Erdal
P.,Erdal
Erdal, Panayirci
Panayırcı E.

Job Title

Prof. Dr.

Email Address

eepanay@khas.edu.tr

ORCID ID

0000-0001-7328-6626

Scopus Author ID

7005179513

Full item page

Scholarly Output

46

Articles

17

Citation Count

298

Supervised Theses

6 Scholarly Output Search Results

Now showing 1 - 10 of 31

Citation Count: 1
Energy-Efficient Design for Reconfigurable Intelligent Surface Aided Cell-Free Ultra Dense HetNets
(Institute of Electrical and Electronics Engineers Inc., 2023) Panayırcı, Erdal; Hu,Y.; Dong,Z.; Panayirci,E.; Jiang,H.; Wu,Q.
In this article, we investigate the energy efficiency (EE) of reconfigurable intelligent surfaces (RISs) aided cell-free ultra-dense HetNets (CFUDN). To maximize the EE of CFUDN, users (UEs) association and clustering, RISs subsurface (SSF) associations are carefully designed. Then, the phase shift matrix of RISs and transmission power of base stations (BSs) are jointly optimized. Due to the non-convexity and high complexity of the formulated problem, this jointly optimized problem is usually difficult to solve. At present, the most commonly adopted method to deal with joint optimization problems is the block coordinate descent (BCD) algorithm based on an alternative optimization framework. However, as we all know, the BCD algorithm has some degree of performance loss due to the alternate optimization of variables. To overcome this challenging issue, a novel joint optimization framework based on Riemannian product manifolds (RPM) is proposed, in which the phase shift matrix of RISs and transmission power of BSs can be simultaneously optimized rather than alternating ways. The simulation results and computational complexity analysis demonstrate that the joint optimization framework based on the RPM exhibits superior performance and lower complexity compared to the joint optimization algorithm based on the BCD. © 2023 IEEE.
Citation Count: 0
Energy-Efficient Design for RIS-Aided Cell-Free Ultra Dense HetNets
(Institute of Electrical and Electronics Engineers Inc., 2023) Panayırcı, Erdal; Hu,Y.; Dong,Z.; Panayirci,E.; Jiang,H.; Wu,Q.
In this article, we investigate the energy efficiency of reconfigurable intelligent surfaces (RISs) aided full-duplex cellfree ultra dense hetNets (CFUDN), which has the advantages of both cell-free massive MIMO (CF-MMIMO) and ultra-dense hetNets (UDN). To maximize the EE of full-duplex CFUDN, users association and clustering, RISs subsurface associations are carefully designed. Then, the phase shift matrix of RISs and transmission power of base stations are jointly optimized. Due to the non-convexity and high complexity of formulated problem, it is extremely difficult to solve this problem. At present, the block coordinate descent (BCD) algorithm is the most commonly used method for joint optimization problems. However, as we all know, the BCD algorithm has some degree of performance loss due to alternate optimization. To overcome this challenging issue, a novel joint optimization framework based on Riemannian product manifolds (RPM) is proposed. © 2023 IEEE.
Citation Count: 48
Optical OFDM with index modulation for visible light communications
(Institute of Electrical and Electronics Engineers Inc., 2015) Panayırcı, Erdal; Panayırcı, Erdal
In this paper we propose optical orthogonal frequency division multiplexing with index modulation (O-OFDM-IM) for visible light communications (VLC) systems employing light emitting diodes (LEDs) and photodetectors (PDs). The proposed scheme uses the indices of the active subcarriers of an optical OFDM system to transmit additional information bits. In the proposed scheme the bipolar signals are asymmetrically clipped or DC biased and a log-likelihood ratio (LLR) calculation based detector is used to determine the indices of the active subcarriers. Our computer simulations show that the O-OFDM-IM achieves better error peformance compared to classical optical OFDM schemes. © 2015 IEEE.
Citation Count: 4
Guest editorial: special issue on high mobility wireless communications
(2012) Panayırcı, Erdal; Panayırcı, Erdal; Li, Ping; Wang, Chengxiang; Tarokh,Vahid
[Abstract Not Available]
Citation Count: 5
Monte Carlo Solutions for Blind Phase Noise Estimation
(Springer International Publishing Ag, 2009) Panayırcı, Erdal; Duyck, Dieter; Cirpan, Hakan Ali; Panayırcı, Erdal; Moeneclaey, Marc
This paper investigates the use of Monte Carlo sampling methods for phase noise estimation on additive white Gaussian noise (AWGN) channels. The main contributions of the paper are (i) the development of a Monte Carlo framework for phase noise estimation with special attention to sequential importance sampling and Rao-Blackwellization (ii) the interpretation of existing Monte Carlo solutions within this generic framework and (iii) the derivation of a novel phase noise estimator. Contrary to the ad hoc phase noise estimators that have been proposed in the past the estimators considered in this paper are derived from solid probabilistic and performance-determining arguments. Computer simulations demonstrate that on one hand the Monte Carlo phase noise estimators outperform the existing estimators and on the other hand our newly proposed solution exhibits a lower complexity than the existing Monte Carlo solutions. Copyright (C) 2009 Frederik Simoens et al.
Modelling of visible light channels and performance analysis for optical ofdm systems
(Kadir Has Üniversitesi, 2016) Panayırcı, Erdal; Panayırcı, Erdal
This work is concerned with a challenging problem of modeling and simulation of visible light communications (VLC) channels for optical wireless communication (OWC) systems. A proper channel model for VLC is absent in the current literature. For this reason two different indoor channel model with different material types and different receiver-transmitter locations have been obtained and implemented for asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) technique. The channel models have been obtained from optical and illumination design software Zemax® by using sequential and non- sequential ray-tracing capabilities for VLC spectrum. The results of implementation of the realistic channel model has significant diversity from Gaussian and infra-red (iR) channel models implemented in studies.
Citation Count: 0
EM-MAP based initialization of PIC receiver for downlink MC-CDMA systems
(IEEE, 2007) Panayırcı, Erdal; Cirpan, Hakan Ali; Panayırcı, Erdal
The quality of multiple access interference (MAI) which can be improved by using channel estimation and data estimation of all active users effects considerably the performance of PIC detector. Therefore data and channel estimation performance is obtained in the initial stage has a significant relationship with the performance of PIC. So obviously it is necessary to make excellent joint data and channel estimation for initialization of PIC detector. In this work to initiate PIC module efficiently a joint MAP channel estimation and data detection technique based on the Expectation Maximization (EM) method has been proposed. Moreover the MAP-EM approach considers the channel variations as random processes and applies the Karhunen-Loeve (KL) orthogonal series expansion. The performance of the proposed approach are studied in terms of bit-error rate (BER). Throughout the simulations extensive comparisons with previous works in literature are performed showing that the new scheme can offer superior performance.
Femtocell design for data communications in mobile networks
(Kadir Has Üniversitesi, 2013) Panayırcı, Erdal; Panayırcı, Erdal
in this thesis game theoretic utility-based adaptive power control algorithm for uplink of femtocell networks is performed for mitigation of interference in two different ways. The first one is allocation of femtocell interference threshold in randomly activated femtocell base stations in a known macrocell coverage area and the second one is adaptation of the power of the femtocell users for mitigating total interference from femtocell users at the macrocell base station. Accordingly we consider two different pricing schemes which are centralized pricing and de-centralized pricing for updating the power level at mobile station. in addition we examined two different technologies which are frequency division multiple access (FDMA) and code DMA (CDMA). The results show that each active user at network could reach the given signal to interference plus noiseratio (SiNR) threshold value with iterative power control algorithm and macrocell base station encountered with given interference threshold value with power control and user removal algorithms. -- Abstract'tan.
Citation Count: 4
Precoded single-cell multi-user MISO visible light communications
(Institute of Electrical and Electronics Engineers Inc., 2015) Panayırcı, Erdal; Haas, Harald; Panayırcı, Erdal
This study investigates the effects of transmitter and receiver parameters on the performance of a precoded singlecell (SC) multi-user (MU) multi-input-single-output (MISO) visible light communication (VLC) system. A zero-forcing (ZF) precoding technique is used within the constraints of optical transmission power and non-negativity of an intensity modulated (IM) transmitted signal. The simulation results show that the physical features of the light emitting diode (LED) and photodiode (PD) have a significant effect on the bit error rate (BER) and total spectral efficiency (SE) performance of the VLC system. The deployment with 8 users and 45o receiver field-of-view (FOV) achieves both the targeted BER and approximately 50 bits/s/Hz total SE when the transmitter semi-angles are 30o and 60o. © VDE Verlag GMBH Berlin Offenbach Germany.
Sparse channel estimation and data detection algorithms for ofdm-based underwater acoustic communication systems
(Kadir Has Üniversitesi, 2018) Panayırcı, Erdal; Panayırcı, Erdal
Communication over acoustic signals in underwater results into a multi-scale multilag channels which occurs due to the multipath propagation. Hence a robust channel estimation technique has to be present at the receiver and the solutions of the terrestrial-based systems are not applicable. in this work using path-based channel model that characterizes underwater channels by a delay a Doppler shift and an attenuation factors three new pilot assisted time domain-based channel estimation algorithms are proposed for single-input single-output communicationbased and diversity communication-based underwater acoustic systems. The multicarrier transmission technique assumed is OFDM. in addition depending on the base stations deployment in underwater the sparse underwater channels undergo Rician or Rayleigh fading where channels in this work are generated using Bellhop software. in the first two proposed approach the overall sparse channel tap delays and constant Doppler shifts are estimated using Matching Pursuit and Orthogonal Matching Pursuit algorithms where the sparse complex channel path gain vector is estimated by maximum a posteriori probability (MAP) technique and the prior densities of the channel gains follow Rician distribution with unknown mean and variance vectors where Maximum Likelihood is proposed for their estimation. The first approach considers a colored noise and uniform Doppler spread and the second approach considers a non-uniform Doppler shifts with white noise. The third proposed approach considers transmitter diversity with Alamouti’s coding where the channel estimator iteratively estimates the complex channel parameters of each subcarrier using the expectation maximization method which in turn converges to a true maximum a posteriori probability estimation of the unknown channel where Karhunen-Loeve expansion and ESPRiT algorithm are assumed for complexity reduction and delay estimation respectively. Finally in ii order to assess the performance of the proposed algorithms the computer simulations show the behavior in terms of mean square error and symbol error rate.