Tunçer Baykaş

Baykaş, Tunçer

Name Variants

B.,Tuncer
Baykaş, Tunçer
Tunçer Baykaş
Baykaş T.
Baykaş, T.
T. Baykaş
B., Tuncer
Baykas, Tuncer
B., Tunçer
BAYKAŞ, Tunçer
Baykas,T.
Baykaş, TUNÇER
Baykas T.
Baykaş,T.
TUNÇER BAYKAŞ
Tunçer BAYKAŞ
BAYKAŞ, TUNÇER
Tuncer, Baykas
Baykas,Tuncer
Baykaş, Tunçer

Job Title

Doç. Dr.

Email Address

tuncer.baykas@khas.edu.tr

ORCID ID

0000-0001-9535-2102

Scopus Author ID

24328990900

Full item page

Scholarly Output

30

Articles

12

Citation Count

150

Supervised Theses

1 Scholarly Output Search Results

Now showing 1 - 10 of 27

Citation Count: 1
Busy Tone Based Power Control for Coordination of Iffy 802.11af and 802.22 System
(IEEE, 2017) Ülgen, Oğuz; Erküçük, Serhat; Karatalay, Onur; Baykas, Tuncer
In 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.
Citation Count: 112
Ieee 802.15.7r1 Reference Channel Models for Visible Light Communications
(IEEE-Inst Electrical Electronics Engineers Inc, 2017) Miramirkhani, Farshad; Narmanlıoğlu, Ömer; Baykas, Tuncer; Uysal, Murat; Panayırcı, Erdal
The IEEE has established the standardization group 802.15.7r1 "Short Range Optical Wireless Communications", which is currently in the process of developing a standard for visible light communication (VLC). As with any other communication system, realistic channel models are of critical importance for VLC system design, performance evaluation, and testing. This article presents the reference channel models that were endorsed by the IEEE 802.15.7r1 Task Group for evaluation of VLC system proposals. These were developed for typical indoor environments, including home, office, and manufacturing cells. While highlighting the channel models, we further discuss physical layer techniques potentially considered for IEEE 802.15.7r1.
Citation Count: 0
A Novel Indoor Channel Model for Tvws Communications Based on Measurements
(IEEE, 2018) Hashir, Syed Muhammad; Erküçük, Serhat; Baykaş, Tunçer
In this paper we present an indoor measurement campaign for TV white space bands inside a university building. The measurement results are compared with different indoor propagation models in the literature. We observed large estimation errors for the total path loss value from all existing models. Consequently we are proposing a new indoor propagation model for TVWS frequencies which concatenates the effects of frequency dependent path loss with penetration losses due to walls and windows. Performance comparison with existing models show that the proposed model achieves superior performance compared to existing models in terms of Root-Mean-Squared Error (RMSE).
Scma Sistemlerinin Performans İncelemeleri
(2023) Tüfekçi, Tolga Kağan; Baykaş, Tunçer
Sürekli yükselen; veri hızı, düşük gecikme, spektral verimlilik ve veri hacmi ihtiyaçlarını karşılayabilmek adına yeni haberleşme yöntemleri geliştirilmektedir. Seyrek Kodlu Çoklu Erişim (Sparse Code Multiple Access - SCMA) bu tekniklerin arasında yer almaktadır. SCMA, dikgen olmayan çoklu erişim (Non-orthogonal Multiple Access - NOMA) yöntemidir. SCMA ile farklı kullanıcılar aynı frekans kaynaklarına atanmasından dolayı spektral verimlilik arttırılır. Her kullanıcıya; seyrek, çok boyutlu ve kompleks değerli kod kitapları atanır, bu sebeple SCMA sistemlerinin performansı da kod kitaplarının kalitesine bağlıdır. Bu tezde; SCMA sistemlerinin farklı senaryolar altındaki performansları incelenmiştir bunlar, 1) Hızlı Sönümlenen Rayleigh Kanallarının etkisi incelenmiş ve bu kanal tipinin SCMA performansındaki negatif etkileri azaltabilmek adına Hızlı Mesaj İletim Algoritması (High-Rate MPA) önerilmiştir. 2) Dikgen ve dikgen olmayan pilot sekansları ve bu sekanslardan yola çıkarak En Küçük Kareler Kestirimi (Least Squares Estimation) yapılmıştır. 3) Simgelerarası Karışmanın (Intersymbol Interference - ISI), SCMA sistemleri üzerindeki etkisi ve PN Sekanslarının üretimi ve kullanımı incelenmiştir. 4) Literatürde bulunan farklı kod kitaplarının SCMA sistemlerindeki performansı incelenmiş ve ayrıca Genetik Algoritma tabanlı bir kod kitabının tasarımı ve yine etkisi incelenmiştir.
Citation Count: 0
Analysis and Optimization of the Network Throughput in IEEE 802.15.13 based Visible Light Communication Networks
(IEEE, 2021) Bulbul, Yusuf; Elamassie, Mohammed; Baykas, Tuncer; Uysal, Murat
In line with the growing interest on visible light communication (VLC), IEEE has initiated standardization efforts on this emerging technology. In this work, we consider IEEE 802.15.13 Optical Wireless Personal Area Networks (OWPAN) standard draft. The underlying MAC protocol uses contention free and contention access periods. For a standard-compliant VLC network, we analyze the network load and propose an algorithm to improve the network throughput by proper selection of period lengths. Our suggested algorithm improves the network performance by at least 5% in the case of variable network traffic up to 15 active users.
Citation Count: 1
A 130 nm CMOS Receiver for Visible Light Communication
(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Ksack, Rifat; Yagan, Muhammed Yaser; Uysal, Murat; Pusane, Ali Emre; Baykas, Tuncer; Dundar, Gunhan; Yalcinkaya, Arda Deniz
Visible light communication (VLC) is an emerging technology that has been gaining attention over the last few years. Transmission of data at higher rates in a VLC system is mainly limited by the modulation bandwidth of the employed LED. To alleviate this limitation, equalization is frequently employed. This is usually achieved by either using discrete circuit elements or in digital form. In this paper, we present a power-efficient VLC receiver as a system-on-chip, implemented in 130 nm CMOS technology. The proposed receiver supports LEDs with different bandwidths thanks to the switchable equalizer. We tested the proposed receiver using phosphorescent white LEDs with different bandwidths on an experimental VLC link. For each tested LED, around 20 fold improvement in data rate was achieved compared to the original bandwidth of the LED. For the LED with a modulation bandwidth of 1.6 MHz, data rates of 32 Mbps and 50 Mbps at a BER of 10(-2) were obtained at a distance of 2 meters without and with a blue filter, respectively.
Citation Count: 7
Regression of Large-Scale Path Loss Parameters Using Deep Neural Networks
(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Bal, Mustafa; Marey, Ahmed; Ates, Hasan F.; Baykas, Tuncer; Gunturk, Bahadir K.
Path loss exponent and shadowing factor are among important wireless channel parameters. These parameters can be estimated using field measurements or ray-tracing simulations, which are costly and time-consuming. In this letter, we take a deep neural network-based approach, which takes either satellite image or height map of a target region as input, and estimates the desired channel parameters. We use the well-known VGG-16 architecture, pretrained on the ImageNet dataset, as the backbone to extract image features, modify it as a regression network to produce channel parameters, and retrain it on our dataset, which consists of satellite image or height map as input and channel parameters as target values. We demonstrate that deep networks can be successfully utilized in estimating path loss exponent and shadowing factor of a region, simply from the region's satellite image or height map. The trained models and test codes are publicly available on a Github page.
Citation Count: 1
Analysis of deep learning based path loss prediction from satellite images
(IEEE, 2021) Alam, Muhammad Z.; Ates, Hasan F.; Baykas, Tuncer; Gunturk, Bahadir K.
Determining the channel model parameters of a wireless communication system, either by measurements or by running electromagnetic propagation simulations, is a time-consuming process. Any rapid deployment of network demands faster determination of at least major channel parameters. In this paper, we investigate the idea of using deep convolutional neural networks and satellite images for channel parameters (i.e., path loss exponent n and shadowing factor sigma) prediction in a cellular network with aerial base stations. Specifically, we investigate the performance dependency of the method on three different factors: height of the transmitter antenna, quantization levels of the channel parameters and architectural design of CNN. The results presented in this paper show a high prediction accuracy of the channel parameters in real-time.
Citation Count: 0
IEEE 802.11BB Reference Channel Models For Light Communications
(Institute of Electrical and Electronics Engineers Inc., 2023) Miramirkhani,F.; Baykas,T.; Elamassie,M.; Uysal,M.
Increasing industrial attention to visible light communications (VLC) technology led the IEEE 802.11 to establish the task group 802.11bb 'Light Communications' (LC) for the development of a VLC standard. As a part of the standard development process, the development of realistic channel models according to possible use cases is of critical importance for physical layer system design. This article presents the reference channel models for the mandatory usage models adopted by IEEE 802.11bb for the evaluation of system proposals. The use cases include industrial, medical, enterprise, and residential scenarios. Channel impulse responses and corresponding frequency responses are obtained for each use case using a ray tracing approach based on realistic specifications for transmitters and receivers, and optical characterization of the environment. © 2023 IEEE.
Citation Count: 8
Location Aware Vertical Handover in a VLC/WLAN Hybrid Network
(IEEE-Inst Electrical Electronics Engineers Inc, 2021) Zeshan, Arooba; Baykas, Tuncer
Visible light communication (VLC) has emerged as a promising technology for wireless communication as it offers higher data rates and secure data transmission along with providing indoor illumination. However, VLC is restricted by the line of sight (LoS) nature of the optical channel that consequently results in light path blockages. Therefore, an effective solution would be to combine VLC with a radio frequency (RF) system to form a hybrid VLC/RF network that would take into account the preferences of an end-user with the practicality of implementation. In such networks, an efficient vertical handover (VHO) technique is the most critical element as it ensures a seamless transition between the two networks. In this work, we propose a vertical handover technique that utilizes the user's location information to make a handover decision. We found that the frequency of light path blockages increases with the increasing number of users in a confined space, resulting in significant performance deterioration. This additional information is then utilized so that the VHO algorithm effectively selects the most feasible network. The proposed algorithm has been tested against the immediate vertical handover algorithm (I-VHO) and the dwell vertical handover algorithm (D-VHO) with two different dwell times. The average number of handovers, quality of experience (QoE), and packet loss have been set as performance metrics. We show from several simulation scenarios that the proposed method results in a fewer number of handovers while maintaining higher QoE and lower packet loss.