Yalçın Şadi

Şadi, Yalçın

Name Variants

ŞADI, Yalçın
Şadi,Y.
Sadi,Y.
Yalçın Şadi
ŞADI, YALÇIN
Şadi, Y.
Sadi, Y.
Y. Sadi
Yalçın ŞADI
YALÇIN ŞADI
Sadi,Yalcin
S., Yalcin
Sadi, Yalçın
Şadi, Yalçın
Yalçın Sadi
Sadi Y.
Ş., Yalçın
Y. Şadi
Şadi, YALÇIN
Sadi, Yalcin
Yalcin, Sadi
S.,Yalcin
Şadi Y.
Şadi, Yalçın

Job Title

Dr. Öğr. Üyesi

Email Address

yalcin.sadi@khas.edu.tr

ORCID ID

0000-0002-8378-5688

Scopus Author ID

36844802900

Full item page

Scholarly Output

28

Articles

11

Citation Count

148

Supervised Theses

4 Scholarly Output Search Results

Now showing 1 - 10 of 26

Citation Count: 13
Qos-Constrained Semi-Persistent Scheduling of Machine-Type Communications in Cellular Networks
(IEEE, 2019) Karadağ, Göksu; Gül, Recep; Sadi, Yalçın; Ergen, Sinem Coleri
The dramatic growth of machine-to-machine (M2M) communication in cellular networks brings the challenge of satisfying the quality of service (QoS) requirements of a large number of M2M devices with limited radio resources. In this paper we propose an optimization framework for the semi-persistent scheduling of M2M transmissions based on the exploitation of their periodicity with the goal of reducing the overhead of the signaling required for connection initiation and scheduling. The goal of the optimization problem is to minimize the number of frequency bands used by the M2M devices to allow fair resource allocation of newly joining M2M and human-to-human communications. The constraints of the problem are delay and periodicity requirements of the M2M devices. We first prove that the optimization problem is NP-hard and then propose a polynomial-time heuristic algorithm employing a fixed priority assignment according to the QoS characteristics of the devices. We show that this heuristic algorithm provides an asymptotic approximation ratio of 2.33 to the optimal solution for the case where the delay tolerances of the devices are equal to their periods. Through extensive simulations we demonstrate that the proposed algorithm performs better than the existing algorithms in terms of frequency band usage and schedulability.
Citation Count: 0
Noma-Based Radio Resource Allocation for Machine Type Communications in 5g and Beyond Cellular Networks
(IEEE, 2021) Aldemir, Sumeyra; Sadi, Yalcin; Erkucuk, Serhat; Okumus, F. Batuhan
In this paper, the minimum bandwidth resource allocation problem for non-orthogonal multiple access (NOMA) based machine to machine (M2M) communications in 5G and beyond cellular networks is investigated. In order to solve the problem fast and efficiently, a persistent resource allocation based polynomial-time algorithm considering NOMA and the periodicity of the machine type communication traffic is proposed. The algorithm consists of two phases. In first phase, M2M clusters are divided into NOMA sub-clusters using a technique that minimizes the number of NOMA sub-clusters for a set of devices. In second phase, NOMA sub-clusters are allocated to resource blocks (RB) considering their quality of service (QoS) requirements while achieving minimum bandwidth reservation. Through simulations, the performance of the proposed algorithm is presented in comparison to the previously proposed access grant time interval (AGTI) based radio resource allocation algorithms. It is illustrated that the proposed algorithm improves the spectrum-efficiency significantly.
Citation Count: 27
Joint Optimization of Wireless Network Energy Consumption and Control System Performance in Wireless Networked Control Systems
(IEEE-INST Electrical Electronics Engineers Inc, 2017) Şadi, Yalçın; Ergen, Sinem Coleri
Communication system design for wireless networked control systems requires satisfying the high reliability and strict delay constraints of control systems for guaranteed stability with the limited battery resources of sensor nodes despite the wireless networking induced non-idealities. These include non-zero packet error probability caused by the unreliability of wireless transmissions and non-zero delay resulting from packet transmission and shared wireless medium. In this paper we study the joint optimization of control and communication systems incorporating their efficient abstractions practically used in real-world scenarios. The proposed framework allows including any non-decreasing function of the power consumption of the nodes as the objective any modulation scheme and any scheduling algorithm. We first introduce an exact solution method based on the analysis of the optimality conditions and smart enumeration techniques. Then we propose two polynomial-time heuristic algorithms based on intelligent search space reduction and smart searching techniques. Extensive simulations demonstrate that the proposed algorithms perform very close to optimal and much better than previous algorithms at much smaller runtime for various scenarios.
Citation Count: 6
Minimum Length Scheduling for Discrete-Rate Full-Duplex Wireless Powered Communication Networks
(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Iqbal, Muhammad Shahid; Sadi, Yalcin; Coleri, Sinem
Wireless powered communication networks (WPCNs) will act as a major enabler of massive machine type communications (MTCs), which is a major service domain for 5G and beyond systems. The MTC networks will be deployed by using low-power transceivers with finite discrete configurations. This paper considers minimum length scheduling problem for full-duplex WPCNs, where users transmit information to a hybrid access point at a rate chosen from a finite set of discrete-rate levels. The optimization problem considers energy causality, data and maximum transmit power constraints, and is proven to be NP-hard. As a solution strategy, we define the minimum length scheduling (MLS) slot, which is slot of minimum transmission completion time while starting transmission at anytime after the decision time. We solve the problem optimally for a given transmission order based on the optimality analysis of MLS slot. For the general problem, we categorize the problem based on whether the MLS slots of users overlap over time. We propose optimal algorithm for non-overlapping scenario by allocating the MLS slots, and a polynomial-time heuristic algorithm for overlapping scenario by allocating the transmission slot to the user with earliest MLS slot. Through simulations, we demonstrate significant gains of scheduling and discrete rate allocation.
Citation Count: 8
Throughput Maximization in Discrete Rate Based Full Duplex Wireless Powered Communication Networks
(John Wıley & Sons Ltd, 2020) Iqbal, Muhammad Shahid; Şadi, Yalçın; Coleri, Sinem
In this study, we consider a discrete rate full-duplex wireless powered communication network. We characterize a novel optimization framework for sum throughput maximization to determine the rate adaptation and transmission schedule subject to energy causality and user transmit power. We first formulate the problem as a mixed integer nonlinear programming problem, which is hard to solve for a global optimum in polynomial-time. Then, we investigate the characteristics of the solution and propose a polynomial time heuristic algorithm for rate adaptation and scheduling problem. Through numerical analysis, we illustrate that the proposed scheduling algorithm outperforms the conventional schemes such as equal time allocation half-duplex and on-off transmission schemes for different initial battery levels, hybrid access point transmit power and network densities.
Semi Persistent Radio Resource Allocation for Machine Type Communications in 5g and Beyond Cellular Networks
(Kadir Has Üniversitesi, 2018) Haj Hussıen, Zaid; Şadi, Yalçın
The fast growth of machine-to-machine (M2M) communications in cellular networks brings the challenge of satisfying diverse Quality-of-Service (QoS) requirements of massive number of machine type communications (MTC) devices with limited radio resources. in this study we first introduce the minimum bandwidth resource allocation problem for M2M communications in 5G and beyond cellular networks. NP-hardness of the problem is proven. Then we propose a fast and efficient polynomial-time algorithm exploiting the periodicity of the MTC traffic based on persistent resource allocation. We prove a mathematical performance result for this algorithm considering a special case of the problem. We elaborate on the expected flexible physical layer structure and study its possible effects on our algorithm. Simulations show that the proposed algorithm outperforms the previously proposed clustering-based radio resource algorithms significantly and performs very close to optimal.
Citation Count: 1
The Effect of Codebook Design on the Conventional SCMA System Performance
(Institute of Electrical and Electronics Engineers Inc., 2020) Kiraci, F.; Bardakci, E.; Sadi, Y.; Erkucuk, S.
In 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 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 study, a conventionally used codebook design in the literature has been considered and the system performance has been improved by increasing the distance between the signal constellation points. Considering two different design approaches, the conventional codebook has been modified and about 1dB gain has been achieved in the high signal-to-noiseratio (SNR) region. © 2020 IEEE.
Citation Count: 0
Resource Allocation for Discrete Rate Multi-Cell Energy Constrained Communication Networks
(Springer, 2024) Iqbal, Muhammad Shahid; Salik, Elif Dilek; Sadi, Yalcin; Coleri, Sinem
Radio frequency energy harvesting is a promising technique to extend the lifetime of wireless powered communication networks (WPCNs) due to its controllability. In this paper, we consider a novel discrete rate based multi-cell WPCN, where multiple hybrid access points (HAPs) transmit energy to the users and users harvest this energy for the information transmission by using a transmission rate selected from a finite set of discrete rate levels. We formulate an optimization problem to minimize the schedule length through optimal rate allocation and scheduling of the users while considering the traffic demand, energy causality and interference constraints. The problem is mixed integer non-linear programming problem. Initially, we investigate the problem for non-simultaneous and simultaneous transmission considering both predetermined and variable transmission rates. We propose optimal and heuristic algorithms for all these categories by using optimality analysis, Perron-Frobenius conditions and iterative improvement of the total schedule length. Then, for the general problem, we propose heuristic algorithm based on the maximization of the number of concurrently transmitting users within each time slot by considering the maximum allowed interference level of the users. Via extensive simulations, we demonstrate significant improvement in schedule length through rate selection and proper scheduling of concurrently transmitting users.
Quality of Service Constrained Scheduling for Massive M2m Communications in Future Cellular Networks
(Kadir Has Üniversitesi, 2018) Mohemine, Muhammad Abdul; Şadi, Yalçın
Radio resource allocation for massive M2M communications is one of the key problems in next generation cellular networks. Satisfying strict and very diverse quality-of-service requirements increases the hardness of this problem. in this thesis flexible scheduling problem for massive M2M communications is solved considering the physical layer architecture of 5G cellular networks. First envisioned physical layer architectures and waveforms proposed for 5G are investigated and a physical layer architecture model that will allow flexible resource allocation is proposed. Then a flexible radio resource allocation algorithm is proposed based on this model. The performance of the algorithm is shown through extensive simulations.
Citation Count: 10
Flexible Physical Layer Based Resource Allocation for Machine Type Communications Towards 6g
(Institute of Electrical and Electronics Engineers Inc., 2020) Şadi, Yalçın; Erküçük, Serhat; Panayırcı, Erdal
The 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.