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    Enhancing performance of M2M random access in 3GPP LTE networks
    (Ieee, 2017) Balcı, Abdullah; Sokullu, Radosveta; Akkaş, Mustafa Alper
    The proliferation of smart devices that can autonomously connect and exchange information over the internet has given rise to a new dynamic area of research, Machine-to-Machine (M2M) communications. M2M refers to networks, which connect devices together and enable them to make smart decisions based on the generated and/or transferred data. The most viable option of implementing M2M communications is over cellular networks. These networks are designed for Human-to-Human (H2H) communication, which is characterized by smaller number of connection requests and longer connection times as compared to the thousands of M2M that will try to connect simultaneously to transmit only a minimum amount of data. When such enormous number of devices is introduced, the existing network will be exposed to high collision rate and extreme connection delays. In LTE, the uplink resources for random access (RA) procedure will be insufficient, and the number of successfully connected devices will bottom out. 3GPP has proposed some solutions to overcome the congestion during the random access procedure. Access Class Barring (ACB) is the most efficient method which increases the access success rate, but it has a disadvantage in terms of access delay. In this paper, we propose to control the ACB parameters adaptively in order to maximize the use of RA resources. Different from other existing methods, our method is based on predicting the number of accessing devices at the beginning of each RA slot and then adjusting the ACB parameters accordingly. Our results show that, the proposed scheme improves delay up to nearly 70% and converges to optimal throughput.
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    Investigation of environmental effects in terahertz band vehicular communication
    (Institute of Electrical and Electronics Engineers Inc., 2022) Körpe, Enis; Akkaş, Mustafa Alper; Sokullu, Radosveta
    Terahertz (THz) waves are electromagnetic waves that vary in the range of 0.1-10 THz in the electromagnetic spectrum. It is a band gap that is underexplored and open to new research topics. Filling the gap between radio and optical frequency ranges, THz technology is a promising technology for next-generation wireless networks. It causes less damage to tissues than X-rays. When it comes to vehicular communication, the technologies used for vehicular communication today have begun to be insufficient in the rapidly increasing data traffic. New technologies are needed to support less latency, higher reliability, and more users. THz technology is considered to be a candidate technology that can meet these specifications. In this paper, the effects of environmental factors such as reflection, scattering and absorption on the transmission in different specific THz vehicular communication scenarios are investigated. The opportunities and drawbacks brought by the THz band for vehicular communication are also introduced. © 2022 IEEE.
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    IoT supported smart home for the elderly
    (Elsevier, 2020) Sokullu, Radosveta; Akkas, Mustafa Alper; Demir, Eren
    Continuously progressing technology helps improve human living standards and make human life easier. A large portion of these developments is targeting the healthcare sector and especially in the last decade has been focused on helping elderly patients extend their independent existence in their preferred environments. In this article, we present a smart home IoT based system for elderly people and people with partial memory loss (MCI patients, dementia patients etc) which ensures their safety and provides early warnings to help them overcome small everyday problems typical for such disorders. Data is continuously collected from various ambient sensors and is used for the contextual detection of their activities. Unobtrusively monitoring the patient's behaviour in his/her home is assured as well as providing necessary data to relatives and/or caregivers. An emergency wristband is added to deal with extraordinary and dangerous situations like unexpected fall, gas/water left open in the house, etc. The developed prototype is a low-cost solution, under 100 USD, in which low energy consumption and ease of integration help greatly increase its applicability. (C) 2020 Elsevier B.V. All rights reserved.
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    An IoT-based greenhouse monitoring system with Micaz motes
    (Elsevier Science Bv, 2017) Akkaş, Mustafa Alper; Sokullu, Radosveta
    The wireless sensor network (WSN) is one of the most significant technologies in the 21st century and they are very suitable for distributed data collecting and monitoring in tough environments such as greenhouses. The other most significant technologies in the 21(st) century is the Internet of Things (IoT) which has rapidly developed covering hundreds of applications in the civil, health, military and agriculture areas. In modern greenhouses, several measurement points are required to trace down the local climate parameters in different parts of a large scale greenhouse in order to ensure proper operation of the greenhouse automation system. Cabling would make the measurement system expensive, vulnerable and also difficult to relocate once installed. This paper presents a WSN prototype consisting of MicaZ nodes which are used to measure greenhouses temperature, light, pressure and humidity. Measurement data have been shared with the help of IoT. With this system farmers can control their greenhouse from their mobile phones or computers which have internet connection. (c) 2017 The Authors. Published by Elsevier B.V.
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    Path loss analysis for terahertz band single-lane vehicular communication
    (Institute of Electrical and Electronics Engineers Inc., 2023) Körpe, Enis; Akkaş, Mustafa Alper; Sokullu, Radosveta
    The Terahertz (THz) band lies between the millimeter wave and the far infrared band (0.1-10 THz) and has an important potential for 5G and 6G communication systems. It is a band gap open to future research as it has not been sufficiently explored. The THz band promises an ultra-high data rate and capacity. Considering vehicular communications, the rapidly increasing data traffic is excessive for current vehicular communication technologies to handle. New technologies and approaches are thus needed to deliver higher capacity and data rates with lower latency. Therefore, it is acknowledged that THz technology is a promising technology that can meet these requirements. In this study, the propagation of the THz signal in single-lane vehicular communication was examined. Respective path loss analyses were performed using the High-Resolution Transmission Molecular Absorption Database (HITRAN). The obtained results were compared with the measurement results in the existing studies. The effect of reflections on the path loss results of the system was also investigated. © 2023 IEEE.
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    Unmanned aerial vehicle and iot as enabling technologies for 5G: frameworks, applications and challenges
    (Springer, 2020) Sokullu, Radosveta; Akkaş, Mustafa Alper
    From the very beginning the Internet was envisioned to provide connections—first between people and the documents they used, now not only among people but between machines as well. And with the current pace of technology development, Gartner’s predictions rise to include 26 billion devices connected to the internet by 2020 with a global economic added value of $1.9 trillion. Among these the frontline is held by self-driving cars and connected cars. The focus of the chapter is how unmanned aerial vehicles, also simply called drones, can be integrated together with the IoT to become one of the major enablers of 5G and Beyond 5G (B5G) networks. A short introduction into the topic covering the main functionality, advantages and challenges of UAVs is followed by discussing the complementary roles that drones and IoT devices can have in the communication canopy. The second part will concentrate on specific architectural issues, discussing different frameworks and network models that can accommodate UAV and IoT integration. The role of UAVs as major entities in the 5G communication network, the promises and challenges are discussed in detail. Following is an overview of some of the most recent applications based on merging these two technologies, including two ongoing projects.
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    Wireless communications beyond 5 g: teraherzwaves, nano-communications and the internet of bio-nano-things
    (Springer, 2022) Akkaş, Mustafa Alper; Sokullu, Radosveta
    Two promising technologies cosidered for the Beyond 5G networks are the terahertz and nano-technologies. Besides other possible application areas they hold the commitment to numerous new nano-scale solutions in the biomedical field. Nano-technology, as the name implies, examines the construction and design of nano-sized materials. These two interconnected emerging technologies have the potential to find application in quite many areas, one of the most importan being healthcare. This overview paper discusses the specifics of these technologies, their most important characteristics and introduces some of the trends for their application in the healthcare sector. In the first section terahertz frequency radio waves and their specific properties depending on the surrounding environment are discussed, followed by an introduction to nano-scale communications. Terahertz waves mandate the use of nano-scale antennas, which in turn brings us to the concept of nano-scale nodes. Nano-scale nodes are units that can perform the most basic functions of nano-machines and inter-nano-machine communications, which allow distributed nano-machines to perform more complex functions. Beyond 5G the development of these nano-communications is expected to lead to the emergence of new complex network systems. In the second part of this paper the paradigms of the Internet of Nano Things, molecular commnications and the Internet of Bio-Nano Things are discussed followed by details on their integration in healthcare related applications. The main goal of the article is to provide an introduction to these intriguing issues discussing advanced nano-technology enablers for Beyond 5G networks such as terahertz and molecular communications, nano-communications between nano-machines and the Internet of Bio-Nano-Things in light of health related applications.