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Öğe A Blockchain-Based Authentication Protocol for Cooperative Vehicular Ad Hoc Network(Mdpi, 2021) Akhter, A. F. M. Suaib; Ahmed, Mohiuddin; Shah, A. F. M. Shahen; Anwar, Adnan; Kayes, A. S. M.; Zengin, AhmetThe efficiency of cooperative communication protocols to increase the reliability and range of transmission for Vehicular Ad hoc Network (VANET) is proven, but identity verification and communication security are required to be ensured. Though it is difficult to maintain strong network connections between vehicles because of there high mobility, with the help of cooperative communication, it is possible to increase the communication efficiency, minimise delay, packet loss, and Packet Dropping Rate (PDR). However, cooperating with unknown or unauthorized vehicles could result in information theft, privacy leakage, vulnerable to different security attacks, etc. In this paper, a blockchain based secure and privacy preserving authentication protocol is proposed for the Internet of Vehicles (IoV). Blockchain is utilized to store and manage the authentication information in a distributed and decentralized environment and developed on the Ethereum platform that uses a digital signature algorithm to ensure confidentiality, non-repudiation, integrity, and preserving the privacy of the IoVs. For optimized communication, transmitted services are categorized into emergency and optional services. Similarly, to optimize the performance of the authentication process, IoVs are categorized as emergency and general IoVs. The proposed cooperative protocol is validated by numerical analyses which show that the protocol successfully increases the system throughput and decreases PDR and delay. On the other hand, the authentication protocol requires minimum storage as well as generates low computational overhead that is suitable for the IoVs with limited computer resources.Öğe IEEE 802.11 MAC Protokolünün VANET ağlardaki performans modellemesi ve analizi(Oğuzhan Yılmaz, 2020) Karabulut, Muhammet Ali; Shah, A. F. M. Shahen; İlhan, HacıIEEE 802.11 standardı, araçsal tasarsız ağlar (Vehicular Ad Hoc Networks, VANETs) için ortam erişim kontrolü (Medium Access Control, MAC) ve fiziksel (PHY) katmanının özelliklerini tanımlamaktadır. IEEE 802.11 standardında, dağıtılmış koordinasyon işlevi (Distributed Coordination Function, DCF) MAC katmanında kullanılan bir tekniktir. DCF, ortama erişmek için çarpışmadan kaçınma ile taşıyıcı duyarlı çoklu erişim (Carrier Sense Multiple Access with Collision Avoidance, CSMA/CA) tekniğini kullanmaktadır. Ayrıca, gönderim isteği (Request To Send, RTS)/ gönderime uygun (Clear To Send, CTS) mekanizması gizli araç düğümleri problemlerinin üstesinden gelmek için kullanılır. CSMA/CA ve RTS/CTS mekanizmalarının algoritmaları sunulmuştur. Markov zincir modeline dayalı analitik analiz, performansı araştırmak için sunulmuştur. Araç hızı, araç yoğunluğu, çekişme penceresi (Contention Window) ve yeniden iletim limiti (Maximum Retransmision Limit) gibi performansı etkileyebilecek parametreler göz önünde bulundurulmuştur. Performans ölçüleri ve parametreleri arasındaki ilişki incelenmiştir. Veri hızı, paket bırakma oranı (Packet Dropping Rate, PDR) ve gecikme ifadeleri elde edilmiştir. Ayrıca, benzetim sonuçları ile performans analizi doğrulanmıştır. CSMA/CA ve RTS/CTS mekanizmalarının karşılaştırılması sunulmuştur.Öğe OEC-MAC: A Novel OFDMA Based Efficient Cooperative MAC Protocol for VANETS(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA, 2020) Karabulut, Muhammet Ali; Shah, A. F. M. Shahen; İlhan, HacıIn vehicular ad hoc networks (VANETs), mobility between vehicles can cause rapid topology changes with frequent disconnections, which result in collisions and packet losses that make communications unstable. Alternatively, cooperative transmission can increase the reliability of communication by eliminating these problems in VANETS. In heavy traffic conditions, carrier sense multiple access with collision avoidance (CSMA/CA) suffers from collision, and it is not effective when high data rate is required. Therefore, orthogonal frequency division multiple access (OFDMA) is proposed. With the use of OFDMA, throughput is increased and delay is decreased by reducing the probability of collision in high traffic scenario. In this study, a novel OFDMA based efficient cooperative MAC protocol (OEC-MAC) is proposed for VANETs. Subcarrier channels assignment and access mechanisms are provided. The mechanism is presented not only for choosing the appropriate transmission mode but also for selecting the optimum relay. New control messages are defined to support cooperative communication. The performance of OEC-MAC protocol is examined by providing analytical analysis based on Markov chain model. Numerical results are demonstrated, which reveal that OEC-MAC protocol ensures a remarkable increase in throughput and also satisfies the strict delay requirement of 100 ms in VANETs for safety messages (sm). In addition, communication reliability is increased by reducing the packet dropping rate (PDR). Numerical results are compared with existing protocols, and a quantitative comparison is provided. It has been seen form results that proposed OEC-MAC protocol is better than existing schemes, especially under heavy traffic scenarios.Öğe Performance Comparison of PEGASIS, HEED and LEACH Protocols in Wireless Sensor Networks(Manisa Celal Bayar Üniversitesi Fen Bilimleri Enstitüsü, 2023) Al-gburi, Kareem Hameed Ali; Shah, A. F. M. ShahenWireless sensor networks (WSNs) is one of the most emerging and fastest growing fields in the scientific world. The most widely recognized requirement related with sensor network configuration is that sensor hubs have restricted energy spending plans. Typically, when a sensor node's battery cannot be replaced or recharged, its low battery power becomes a serious problem. The efficient use of energy source in a sensor node is a desirable criterion for scalability and prolonging the lifetime of WSN. Therefore, designing an efficient routing protocol for reducing energy consumption is one of the important issues in the network. A large number of routing protocols have been proposed in the last few decades. Some of the most popular and energy efficient routing protocols are hierarchical routing protocols like LEACH (Low Energy Adaptive Clustering Hierarchy), PEGASIS (Power Efficient GAthering in Sensor Information Systems), and HEED (Hybrid Energy Efficient Distributed clustering protocol). In this paper, these hierarchical routing protocols are studied for their pros and cons. Finally, a comparative study on these protocols is done based on several metrics such as: energy consumption, stability period, scalability, and network lifetime through simulations on different simulation environments.Öğe Performance modeling and analysis of the IEEE 802.11 MAC protocol for VANETs(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, BAYAR BULVARI, MALTEPE, ANKARA, 06570, TURKEY, 2020) Karabulut, Muhammet Ali; Shah, A. F. M. Shahen; İlhan, HacıThe IEEE 802.11 standard defines the specifications of the media access control (MAC) and physical (PHY) layers for vehicular ad hoc networks (VANETs). In IEEE 802.11, distributed coordination function (DCF) is the fundamental access technique, which employs a carrier sense multiple access with collision avoidance (CSMA/CA) mechanism to access the medium. In addition, request to send (RTS)/clear to send (CTS) mechanism is used to overcome hidden vehicular nodes problem. In this paper, an analytical model is developed to evaluate the performance of the IEEE 802.11 MAC for VANETs. The algorithm of CSMA/CA and RTS/CTS mechanism are presented. Markov chain model based analytical analysis is presented to investigate the performance. Parameters that can influence the performance such as vehicles velocity, vehicle density, contention window size, maximum retransmission limit etc. are considered. The relationship between the performance metrics and parameters are derived. Throughput, packet dropping rate (PDR) and delay expressions are obtained. Moreover, numerical results are demonstrated to verify the analysis. The comparison between CSMA/CA and RTS/CTS access mechanisms is presented.Öğe Performance Optimization of Cluster-Based MAC Protocol for VANETs(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141, 2020) Shah, A. F. M. Shahen; Karabulut, Muhammet Ali; İlhan, Hacı; Türeli, UfukRecently, a novel cluster-based medium access control (CB-MAC) protocol has been proposed for vehicular ad hoc networks (VANETs). Though performance of CB-MAC protocol is affected by cluster size, no mechanism is provided to manage cluster size efficiently. In this paper, the performance of CB-MAC protocol is optimized for VANETs by optimizing transmission probability with cluster size. Each vehicle should adopt the optimum transmission probability in the cluster which can be obtained by tuning the number of clusters in VANET. Therefore, optimum number of clusters is defined based on the number of vehicles in VANETs. An analytical study based on Markov chain model is provided. Optimum transmission probability, and optimum number of clusters expressions are derived. The microscopic mobility model is generated in SUMO for practical scenario. Simulation results are presented which verify analytical (theoretical) analysis and show that the performance of CB-MAC protocol is maximized in terms of throughput, packet dropping rate (PDR), and delay. Throughput is remarkably increased, whereas PDR and delay are decreased.Öğe A Secured Message Transmission Protocol for Vehicular Ad Hoc Networks(TECH SCIENCE PRESS, 871 CORONADO CENTER DR, SUTE 200, HENDERSON, NV 89052, 2021) Akhter, A. F. M. Suaib; Shah, A. F. M. Shahen; Ahmed, Mohiuddin; Moustafa, Nour; Çavuşoğlu, Ünal; Zengin, AhmetVehicular Ad hoc Networks (VANETs) become a very crucial addition in the Intelligent Transportation System (ITS). It is challenging for a VANET system to provide security services and parallelly maintain high throughput by utilizing limited resources. To overcome these challenges, we propose a blockchain-based Secured Cluster-based MAC (SCB-MAC) protocol. The nearby vehicles heading towards the same direction will form a cluster and each of the clusters has its blockchain to store and distribute the safety messages. The message which contains emergency information and requires Strict Delay Requirement (SDR) for transmission are called safety messages (SM). Cluster Members (CMs) sign SMs with their private keys while sending them to the blockchain to confirm authentication, integrity, and confidentiality of the message. A Certificate Authority (CA) is responsible for physical verification, key generation, and privacy preservation of the vehicles. We implemented a test scenario as proof of concept and tested the safety message transmission (SMT) protocol in a real-world platform. Computational and storage overhead analysis shows that the proposed protocol for SMT implements security, authentication, integrity, robustness, non-repudiation, etc. while maintaining the SDR. Messages that are less important compared to the SMs are called non-safety messages (NSM) and vehicles use RTS/CTS mechanism for NSM transmission. Numerical studies show that the proposed NSM transmission method maintains 6 times more throughput, 2 times less delay and 125% less Packet Dropping Rate (PDR) than traditional MAC protocols. These results prove that the proposed protocol outperforms the traditional MAC protocols.Öğe A Secured Privacy-Preserving Multi-Level Blockchain Framework for Cluster Based VANET(MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2021) Akhter, A. F. M. Suaib; Ahmed, Mohiuddin; Shah, A. F. M. Shahen; Anwar, Adnan; Zengin, AhmetExisting research shows that Cluster-based Medium Access Control (CB-MAC) protocols perform well in controlling and managing Vehicular Ad hoc Network (VANET), but requires ensuring improved security and privacy preserving authentication mechanism. To this end, we propose a multilevel blockchain-based privacy-preserving authentication protocol. The paper thoroughly explains the formation of the authentication centers, vehicles registration, and key generation processes. In the proposed architecture, a global authentication center (GAC) is responsible for storing all vehicle information, while Local Authentication Center (LAC) maintains a blockchain to enable quick handover between internal clusters of vehicle. We also propose a modified control packet format of IEEE 802.11 standards to remove the shortcomings of the traditional MAC protocols. Moreover, cluster formation, membership and cluster-head selection, and merging and leaving processes are implemented while considering the safety and non-safety message transmission to increase the performance. All blockchain communication is performed using high speed 5G internet while encrypted information is transmitted while using the RSA-1024 digital signature algorithm for improved security, integrity, and confidentiality. Our proof-of-concept implements the authentication schema while considering multiple virtual machines. With detailed experiments, we show that the proposed method is more efficient in terms of time and storage when compared to the existing methods. Besides, numerical analysis shows that the proposed transmission protocols outperform traditional MAC and benchmark methods in terms of throughput, delay, and packet dropping rate.Öğe Survey and Performance Evaluation of Multiple Access Schemes for Next-Generation Wireless Communication Systems(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141, 2021) Shah, A. F. M. Shahen; Qasim, Ahmed Nidham; Karabulut, Muhammet Ali; İlhan, Hacı; Islam, Md. BaharulMobile communication systems are always in continuous evolution due to the demands of the end-users using this technology. Therefore, before the possible launch of 5G, some technologies have opened the way to the new mobile communication system. The need for technologies that provide more comfort to users has led to the construction of complex communication systems that were only science fiction decades ago. The information society in which we are now immersed has been the result of constant progress over time. In this paper, a survey of multiple access schemes for next-generation wireless communication systems is presented. Multiple access schemes are reviewed for possible use in next-generation wireless communication systems such as orthogonal multiple access (OMA), non-orthogonal multiple access (NOMA), and delta-orthogonal multiple access (D-OMA), etc. General comparisons of 1G to 6G are presented. Different types of OMA are explained, and then orthogonal frequency division multiple access (OFDMA) is chosen as an example of the OMA scheme to compare with NOMA and D-OMA. There are two types of NOMA: power-domain and code-domain, which are discussed and compared. Simulation results are presented, and a comparison among different access schemes is provided.
