Download or read book An Enhanced Medium Access Control Protocol for Ad Hoc Networks written by Priyadarshini Sabut and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ad hoc Networks are the most popular networks and are useful in many application environments due to less cost and easy deployment at anytime anywhere. The efficiency of these networks depends on the performance and reliability of the medium access control (MAC) protocol applied in such networks. The IEEE 802.11 DCF MAC protocol for ad hoc networks suffers from the problem of bandwidth sharing due to presence of hidden and exposed nodes. This book discusses a MAC protocol that not only overcomes the problem of hidden and exposed nodes but also allows the hidden nodes to transmit and exposed nodes to receive without interfering with the ongoing transmission in their vicinity, thereby improving channel utilization. The proposed protocol outperforms IEEE 802.11 DCF MAC in terms of throughput and packet delivery ratio with a little cost of control overhead.

Download or read book Enhanced Synchronized Medium Access Control Protocol for Wireless Ad Hoc Network written by Shenbo Liu and published by . This book was released on 2006 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis, a new synchronized medium access protocol (MAC), named ES-MAC, for wireless ad hoc networks is proposed. ES-MAC employs a binary-countdown scheme to resolve contentions between wireless systems. There are three coherent phases in the proposed ES-MAC, namely, contention resolution phase, hidden station elimination phase, and data transmission phase. ES-MAC is simple, efficient, fair, and quality of service (QoS) capable. Along with mathematical analysis, a simulator based on GloMoSim is developed. The simulation and analysis results show that ES-MAC can achieve low collision rate and high efficiency at a wide range of traffic load"--Abstract.

Download or read book Medium Access Protocol MAC Design for Wireless Multi hop Ad Hoc and Sensor Networks written by Afef Sayadi and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless multi-hop ad hoc and sensor networks provide a promising solution to ensure ubiquitous connectivity for the Future Internet. Good network connectivity requires designing a reliable Medium Access Control (MAC) protocol, which is a challenging task in the ad hoc and sensor environments. The broadcast and shared nature of the wireless channel renders the bandwidth resources limited and expose the transmissions to relatively high collisions and loss rates. The necessity to provide guaranteed Quality of Service (QoS) to the upper layers triggered the design of conflict-free MAC protocols. The TDMA synchronization constraint is basically behind the rush of MAC protocol design based on a fixed frame size. This design shows inflexibility towards network variations and creates a network dimensioning issue that leads to a famine risk in case the network is under-dimensioned, and to a waste of resources, otherwise. Moreover, the alternative dynamic protocols provide more adaptive solutions to network topology variations at the expense of a fair access to the channel. Alongside with the efficient channel usage and the fair medium access, reducing the energy consumption represents another challenge for ad hoc and sensor networks. Solutions like node activity scheduling tend to increase the network lifetime while fulfilling the application requirements in terms of throughput and delay, for instance. Our contributions, named OSTR and S-OSTR, address the shortcomings of the medium access control protocol design in the challenging environment of wireless multi-hop ad hoc and sensor networks, respectively. For OSTR the idea consists in adopting a dynamic TDMA frame size that increases slot-by-slot according to the nodes arrival/departure to/from the network, and aiming to achieve a minimum frame size. For this end, OSTR couples three major attributes: (1) performing slot-by-slot frame size increase, (2) providing a spatial reuse scheme that favors the reuse of the same slot if possible, (3) and ensuring an on-demand frame size increase only according to the node requirements in terms of throughput. To tackle different frame sizes co-existence in the network, OSTR brings a cooperative solution that consists in fixing an appointment, a date when the frame size in the network is increased. Concerning S-OSTR, it is an amendment of OSTR for wireless sensor networks. It brings the idea of a dynamic active period, since it deploys a dynamic frame size that is built slot-by-slot according to nodes arrival to the network. S-OSTR enforces the slot-by-slot frame size increase by a node activity scheduling to prolong the inactivity period in the network, and hence prolong the overall network lifetime for wireless sensor networks. Our contributions are both based on the new dynamic TDMA frame size increase that consists in increasing the frame size slot-by-slot aiming to achieve a shorter frame size, and hence improve the channel utilization, and reduce the energy consumption. The performance analysis of OSTR and S-OSTR shows that they present good potentials to support QoS requirements, to provide energy-efficiency, to ensure fair medium access, to accommodate network topology changes and finally, to enhance robustness against scalability. The impact of this new TDMA frame size increase technique on the medium access control protocol performance is highlighted through multiple simulations of OSTR and S-OSTR. Multiple comparative studies are also handled to point out the effectiveness of this new technique and the soundness of our contributions.

Download or read book Enhancing the Performance of Ad Hoc Wireless Networks with Smart Antennas written by Somprakash Bandyopadhyay and published by CRC Press. This book was released on 2016-04-19 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large portion of the network capacity of an ad hoc network can be wasted by the medium access mechanisms of omni-directional antennas. To overcome this problem, researchers propose the use of directional or adaptive antennas that largely reduce radio interference, improving the utilization of wireless medium and the resulting network throughput.

Download or read book Enhanced IEEE 802 11 p Based MAC Protocols for Vehicular Ad Hoc Networks written by Yamen Nasrallah and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intelligent Transportation System (ITS) is a cooperative system that relies on reliable and robust communication schemes among vehicles and between vehicles and their surroundings. The main objective of the ITS is to ensure the safety of vehicle drivers and pedestrians. It provides an efficient and reliable transportation system that enhances traffic management, reduces congestion time, enables smooth traffic re-routing, and avoids economic losses. An essential part of the ITS is the Vehicular Ad hoc Network (VANET). VANET enables the setup of Vehicle-to-Vehicle (V2V) as well as Vehicle-to-Infrastructure (V2I) communication platforms: the two key components in the ITS. The de-facto standard used in wireless V2V and V2I communication applications is the Dedicated Short Range Communication (DSRC). The protocol that defines the specifications for the Medium Access Control (MAC) layer and the physical layer in the DSRC is the IEEE 802.11p protocol. The IEEE 802.11p protocol and its Enhanced Distributed Channel Access (EDCA) mechanism are the main focus of this thesis. Our main objective is to develop new IEEE 802.11p-based protocol for V2V and V2I communication systems, to improve the performance of safety-related applications. These applications are of paramount importance in ITS, because their goal is to decrease the rate of vehicle collisions, and hence reduce the enormous costs associated with them. In fact, large percentage of vehicle collisions can be easily avoided with the exchange of relevant information between vehicles and the Road Side Units (RSUs) installed on the sides of the roads. In this thesis, we propose various enhancements to the IEEE 802.11p protocol to improve its performance by lowering the average end-to-end delay and increasing the average network throughput. We introduce multiple adaptive algorithms to promote the QoS support across all the Access Categories (AC) in IEEE 802.11p. We propose two adaptive backoff algorithms and two algorithms that adaptively change the values of the Arbitrary Inter-Frame Space (AIFS). Then we extend our model to be applied in a large-scale vehicular network. In this context, a multi-layer cluster-based architecture is adopted, and two new distributed time synchronization mechanisms are developed.

Download or read book Position Location Techniques and Applications written by David Munoz and published by Academic Press. This book was released on 2009-05-15 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the definitive guide to the techniques and applications of position location, covering both terrestrial and satellite systems. It gives all the techniques, theoretical models, and algorithms that engineers need to improve their current location schemes and to develop future location algorithms and systems. Comprehensive coverage is given to system design trade-offs, complexity issues, and the design of efficient positioning algorithms to enable the creation of high-performance location positioning systems. Traditional methods are also reexamined in the context of the challenges posed by reconfigurable and multihop networks. Applications discussed include wireless networks (WiFi, ZigBee, UMTS, and DVB networks), cognitive radio, sensor networks and multihop networks. Features - Contains a complete guide to models, techniques, and applications of position location - Includes applications to wireless networks, demonstrating the relevance of location positioning to these "hot" areas in research and development - Covers system design trade-offs and the design of efficient positioning algorithms, enabling the creation of future location positioning systems - Provides a theoretical underpinning for understanding current position location algorithms, giving researchers a foundation to develop future algorithms David Muñoz is Director and César Vargas is a member of the Center for Electronics and Telecommunications, Tecnológico de Monterrey, Mexico. Frantz Bouchereau is a senior communications software developer at The MathWorks Inc. in Natick, MA. Rogerio Enríquez-Caldera is at Instituto Nacional de Atrofisica, Optica y Electronica (INAOE), Puebla, Mexico. - Contains a complete guide to models, techniques and applications of position location - Includes applications to wireless networks (WiFi, ZigBee, DVB networks), cognitive radio, sensor networks and reconfigurable and multi-hop networks, demonstrating the relevance of location positioning to these 'hot' areas in research and development - Covers system design trade-offs, and the design of efficient positioning algorithms enables the creation of future location positioning systems - Provides a theoretical underpinning for understanding current position location algorithms, giving researchers a foundation to develop future algorithms

Download or read book Enhanced Medium Access Control Protocol for Resolving Node Misbehavior in Wireless Networks written by Noorsalwati Nordin and published by . This book was released on 2007 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensor and Ad Hoc Networks written by S. Kami Makki and published by Springer Science & Business Media. This book was released on 2010-03-14 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together leading researchers and developers in the field of wireless sensor networks to explain the special problems and challenges of the algorithmic aspects of sensor and ad-hoc networks. The book also fosters communication not only between the different sensor and ad-hoc communities, but also between those communities and the distributed systems and information systems communities. The topics addressed pertain to the sensors and mobile environment.

Download or read book Medium Access Control in Ad Hoc Networks with Omni directional and Directional Antennas written by Yu Wang and published by . This book was released on 2004 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ad hoc network is a dynamic network formed on demand by a group of nodes without the aid of any pre-existing network infrastructure. An efficient and effective medium access control (MAC) protocol which regulates nodes access to the shared channel(s) is essential in an ad hoc network. Our work is focused on the throughput and fairness properties of existing omni-directional MAC protocols as well as enhancement of their performance with directional antennas via both analytical and simulation approaches. In the first part, we present the first analytical modeling of collision avoidance MAC protocols including the popular IEEE 802.11 MAC protocol in multi-hop ad hoc networks. We show that in ad hoc networks with a lot of hidden terminals, collision avoidance even if done correctly, can still limit achievable throughput significantly because of the much reduced spatial reuse. Then we advance the analytical modeling to evaluate those MAC protocols which use directional antennas and can achieve much higher throughput through directing transmissions and receptions to desired directions only. We show that the gain in spatial reuse outweighs that of collision avoidance and hence an aggressive all-directional scheme is more advantageous than other hybrid schemes that take conservative (or unnecessary) tradeoff between collision avoidance and spatial reuse. All the analytical work has provided very useful insight on the interaction between spatial reuse, interference reduction and collision avoidance that previous work lacked.

Download or read book Computational Science ICCS 2007 written by Yong Shi and published by Springer Science & Business Media. This book was released on 2007-05-18 with total page 1247 pages. Available in PDF, EPUB and Kindle. Book excerpt: Part of a four-volume set, this book constitutes the refereed proceedings of the 7th International Conference on Computational Science, ICCS 2007, held in Beijing, China in May 2007. The papers cover a large volume of topics in computational science and related areas, from multiscale physics to wireless networks, and from graph theory to tools for program development.

Download or read book Wireless Network Performance Enhancement via Directional Antennas Models Protocols and Systems written by John D. Matyjas and published by CRC Press. This book was released on 2015-11-18 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directional antenna technologies have made significant advancements in the last decade. These advances have opened the door to many exciting new design opportunities for wireless networks to enhance quality of service (QoS), performance, and network capacity. In this book, experts from around the world present the latest research and development in

Download or read book Adaptation and Cross Layer Design in Wireless Networks written by Mohamed Ibnkahla and published by CRC Press. This book was released on 2018-10-08 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive techniques play a key role in modern wireless communication systems. The concept of adaptation is emphasized in the Adaptation in Wireless Communications Series through a unified framework across all layers of the wireless protocol stack ranging from the physical layer to the application layer, and from cellular systems to next-generation wireless networks. Adaptation and Cross Layer Design in Wireless Networks is devoted to adaptation in the data link layer, network layer, and application layer. The book presents state-of-the-art adaptation techniques and methodologies, including cross-layer adaptation, joint signal processing, coding and networking, selfishness in mobile ad hoc networks, cooperative and opportunistic protocols, adaptation techniques for multimedia support, self –organizing routing, and tunable security services. It presents several new theoretical paradigms and analytical findings which are supported with various simulation and experimental results. Adaptation in wireless communications is needed in order to achieve high capacity and ubiquitous communications. The current trend in wireless communication systems is to make adaptation dependent upon the state of the relevant parameters in all layers of the system. Focusing on simplified cross layer design approaches, this volume describes advanced techniques such as adaptive resource management, adaptive modulation and coding, 4G communications, QoS, diversity combining, and energy and mobility aware MAC protocols. The first volume in the series, Adaptive Signal Processing in Wireless Communications (cat no.46012) covers adaptive signal processing at the physical layer.

Download or read book Cognitive Radio Mobile Ad Hoc Networks written by F. Richard Yu and published by Springer Science & Business Media. This book was released on 2011-09-28 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive radios (CR) technology is capable of sensing its surrounding environment and adapting its internal states by making corresponding changes in certain operating parameters. CR is envisaged to solve the problems of the limited available spectrum and the inefficiency in the spectrum usage. CR has been considered in mobile ad hoc networks (MANETs), which enable wireless devices to dynamically establish networks without necessarily using a fixed infrastructure. The changing spectrum environment and the importance of protecting the transmission of the licensed users of the spectrum mainly differentiate classical MANETs from CR-MANETs. The cognitive capability and re-configurability of CR-MANETs have opened up several areas of research which have been explored extensively and continue to attract research and development. The book will describe CR-MANETs concepts, intrinsic properties and research challenges of CR-MANETs. Distributed spectrum management functionalities, such as spectrum sensing and sharing, will be presented. The design, optimization and performance evaluation of security issues and upper layers in CR-MANETs, such as transport and application layers, will be investigated.

Download or read book Intelligent Quality of Service Technologies and Network Management Models for Enhancing Communication written by Bhattarakosol, Pattarasinee and published by IGI Global. This book was released on 2010-04-30 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This book "quality of service" in organizations, offering fundamental knowledge on the subject, describing the significance of network management and the integration of knowledge to demonstrate how network management is related to QoS in real applications"--Provided by publisher.

Download or read book Wireless Algorithms Systems and Applications written by Kuai Xu and published by Springer. This book was released on 2015-07-31 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of the 10th International Conference on Wireless Algorithms, Systems, and Applications, WASA 2015, held in Qufu, Shandong, China, in August 2015. The 36 revised full papers presented together with 5 revised short papers and 42 invited papers were carefully reviewed and selected from 133 initial submissions. The papers present current trends, challenges, and state-of-the-art solutions related to various issues in wireless networks. Topics of interests include effective and efficient state-of-the-art algorithm design and analysis, reliable and secure system development and implementations, experimental study and testbed validation, and new application exploration in wireless networks. .

Download or read book Characterization Avoidance and Repair of Packet Collisions in Inter Vehicle Communication Networks written by Mittag, Jens and published by KIT Scientific Publishing. This book was released on 2012-08-08 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work proposes a combined and accurate simulation of wireless channel, physical layer and networking aspects in order to bridge the gaps between the corresponding research communities. The resulting high fidelity simulations enable performance optimizations across multiple layers, and are used in the second part of this thesis to evaluate the impact of fast-fading channel characteristics on Carrier-Sense Multiple Access, and to quantify the benefit of successive interference cancellation.

Download or read book Channel Based Medium Access Control for Ad Hoc Wireless Networks written by Manzur Ashraf and published by LAP Lambert Academic Publishing. This book was released on 2010 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work proposed a novel communication protocol for dynamic, distributed wireless networks. This protocol can adapt to users movements as well as the environment changes. A scalable channel prediction scheme is required to implement the practical Channel MAC protocol in practice. We propose a mean-value based channel prediction scheme, which provides prediction with enough accuracy to be used in the Channel MAC protocol. Next, we extend the Channel MAC protocol to support multi-rate communications. We propose a safety margin based technique to provide auto rate adaptation of the multi-rate Channel MAC. The speed, fairness, and resource utilisation in wireless communications are improved by the proposed protocol compared to existing techniques.