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 Cross Layer Optimizations for Performance Enhancement of Wireless Networks written by Tarun Joshi and published by . This book was released on 2006 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we focus on designing several cross-layer optimizations to boost the performance of wireless networks. We categorize our efforts into two directions: (a) improvement of spatial reusability and multi-hop performance via Directional Antennas, and (b) analysis and optimization of the IEEE 802.11 multi-rate networks. Since existing protocols are incapable of fully exploiting the benefits of a directional antenna system, we propose a, broadcast and routing protocol for such systems. All our proposals assume cross layer interaction between the Network, MAC and PHY layers. Next, we analyze multi-rate networks in the context of IEEE 802.11 DCF networks and propose an analytical model to study the link-delay characteristics of such systems. We then propose an online algorithm Time Fair CSMA (TFCSMA), for guaranteeing air-time fairness and thereby mitigating the recently observed rate anomaly problem of IEEE DCF multi-rate networks. Following the design of TFCSMA, we concentrate on the problem of rate adaptation for time-varying wireless channels. We thoroughly investigate the impact of transmission rate on the performance of a wireless link. We then propose Stochastic Automata Rate Adaptation Algorithm (SARA). SARA is inspired by Stochastic Learning Automata (SLA), a machine learning technique for adaptation in random environments. As opposed to the previous work in this area, SARA is ideally suited for both stationary and non-stationary channel environments and is completely compatible with the existing IEEE 802.11 MAC standard.

Download or read book Performance Enhancement by Using PHY Layer Information in Wireless Networks written by Haochao Li and published by . This book was released on 2011 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Enhancement of TCP Over Wireless Network written by Md. Shah Jahan Rahman and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: TCP is the widely used transport protocol across the internet but it was originally designed for wired networks. In wireless networks, TCP encounters serious problems due to the physical properties of the wireless medium. The proposed model has implemented by TCP-LPA (Loss Piece ACK) for wireless network and its performance has compared with that of TCP-DBA (Demand Base ACK). In this thesis, it may be concentrated on two main strategies for enabling the TCP congestion control mechanism to determine the cause for a packet loss. The main objective of our proposed proxy based mechanisms is to explicitly inform the TCP source of any effects caused by wireless links while maintaining the end-to-end design philosophy. However, the implementation technique is network dependent. Finally, it may be developed an analytical TCP throughput model with enhanced TCP-DBA fast retransmit algorithm to avoid timeouts. The model captures the TCP fast retransmit mechanism and expresses the steady state congestion window and throughput as a function of network utilization factor, RTT and loss rate.

Download or read book Performance Enhancement of Wireless Mesh Networks written by Noun Choi and published by . This book was released on 2008 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: With advances in wireless technologies, broadband wireless networks have been increasingly demanded recently. Several approaches are actively discussed in order to provide broadband network access to the mobile users. IEEE 802.16 based WiMAX has been proposed to provide long distance wireless data communication. Cellular network industry is also moving toward the next generation network system which is the fully IP based network.

Download or read book Performance Enhancement in Wireless Local Area Networks written by Daji Qiao and published by . This book was released on 2004 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cross Layer Optimizations for Performance Enhancement in Wireless Networks written by and published by . This book was released on 2008 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we focus on optimizing link layer performance and maximizing throughput in IEEE 802.11 wireless networks. We categorize our efforts into two directions: (a) throughput optimization and analysis of the 802.11 multi-rate networks via rate adaptation (b) design of a new MAC protocol for emerging multipacket reception capable wireless networks. Both our proposals assume cross layer interaction between the MAC and the PHY layers. In the first part of the work, we focus on the use of rate adaptation for throughput gains in time-varying wireless channels. We thoroughly investigate the impact of transmission rate on the performance of a wireless link. We then propose Stochastic Automata Rate Adaptation Algorithm (SARA) inspired by Stochastic Learning Automata (SLA), a machine learning technique for adaptation in random environments. Besides boosting throughput, SARA also provides an integrated and distributed solution for both stationary and non-stationary channel environments. SARA is completely compatible with existing IEEE 802.11 MAC standards. In the second part of the work, we move on to more advanced 802.11 networks that employ techniques like multiple antennas, DS-CDMA codes, spatial diversity techniques etc and have the capability of receiving multiple packets simultaneously. To provide the maximum performance benefits in these networks, we propose the use of a new MAC protocol Receiver-Based Multipacket Reception MAC (RB-MPR MAC) that relies on the use of a Multipacket Reception (MPR) matrix as cross-layer information. The application of MPR matrix, its benefits and limitations, impact of partitioning the network (Grouping) in a DS-CDMA system have been analyzed thoroughly and important results and interpretations have been put forward.

Download or read book Controlled Mobility for Performance Enhancements in Wireless Sensor Networks written by Jayanthi Rao and published by . This book was released on 2009 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Enhancement of WSN Using Improved Cooperative Caching Scheme written by Vikas Wasson and published by . This book was released on 2017-11-16 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wireless network is the collection of nodes without the necessity of any access point in the center. Now a days, wireless networking is hugely used for the commercial purposes and it becomes the newly trend to adapt the wireless networks. There are the many applications for the wireless networks as it lies in the military, tactical and various security sensitive operations. Secure routing is an important issue in the routing applications. The wireless network uses the communication protocols and it uses the air through the operation of the protocols of communication [4]. Wireless networks use a protocol carrier for sensing the synchronization and these protocols are similar to the Ethernet standard. These protocols enable the group of wireless computers to share the same amount of frequency and space. The wireless is a shared media technology as all users share the available bandwidth here

Download or read book Deployment and Performance Enhancement of Wireless Mesh Networks written by Daniel Wu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless mesh networks provide necessary network connectivity in rural and remote locations through multi-hopping. To avoid contention and congestion in the wireless channel and degradation in overall performance, a mesh network must be optimized. This dissertation proposes characterization studies in deployment and performance enhancements of wireless mesh networks. Characterizations in wireless mesh network deployments enable network planners to optimize network equipment usage more efficiently. Studies in performance enhancement techniques also enable researchers to create more efficient algorithms. This dissertation illustrates the deployment and performance enhancements characterizations in three phases. The first phase is a large-scale wireless mesh network deployment in a natural reserve. The QuRiNet deployment provides a testing ground for developing new wireless optimization protocols and acts as a backbone network for remote ecological and network data collection. The second phase is a study of wireless link quality in a network. A well-developed wireless link quality characterization study gives insights into the behavior of a wireless network. The final phase uses the link quality study and the multi-radio multi-channel features of QuRiNet for optimization. Specialized static channel assignment algorithms are evaluated to yield a near-optimal network topology. We compare integer linear programming solutions along with breadth-first search and priority-based selection heuristics to determine which algorithm is suitable for QuRiNet.

Download or read book Wireless Communications Systems and Networks written by Mohsen Guizani and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the early 1990s, the wireless communications field has witnessed explosive growth. The wide range of applications and existing new technologies nowadays stimulated this enormous growth and encouraged wireless applications. The new wireless networks will support heterogeneous traffic, consisting of voice, video, and data (multimedia). This necessitated looking at new wireless generation technologies and enhance its capabilities. This includes new standards, new levels of Quality of Service (QoS), new sets of protocols and architectures, noise reduction, power control, performance enhancement, link and mobility management, nomadic and wireless networks security, and ad-hoc architectures. Many of these topics are covered in this textbook. The aim of this book is research and development in the area of broadband wireless communications and sensor networks. It is intended for researchers that need to learn more and do research on these topics. But, it is assumed that the reader has some background about wireless communications and networking. In addition to background in each of the chapters, an in-depth analysis is presented to help our readers gain more R&D insights in any of these areas. The book is comprised of 22 chapters, written by a group of well-known experts in their respective fields. Many of them have great industrial experience mixed with proper academic background.

Download or read book TCP Performance Enhancement Over Wireless Networks written by Aiyathurai Jayananthan and published by . This book was released on 2007 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Techniques for End to end TCP Performance Enhancement Over Wireless Networks written by Bong Ho Kim and published by . This book was released on 2016 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today’s wireless network complexity and the new applications from various user devices call for an in-depth understanding of the mutual performance impact of networks and applications. It includes understanding of the application traffic and network layer protocols to enable end-to-end application performance enhancements over wireless networks. Although Transport Control Protocol (TCP) behavior over wireless networks is well known, it remains as one of the main drivers which may significantly impact the user experience through application performance as well as the network resource utilization, since more than 90% of the internet traffic uses TCP in both wireless and wire-line networks. In this dissertation, we employ application traffic measurement and packet analysis over a commercial Long Term Evolution (LTE) network combined with an in-depth LTE protocol simulation to identify three critical problems that may negatively affect the application performance and wireless network resource utilization: (i) impact of the wireless MAC protocol on the TCP throughput performance, (ii) impact of applications on network resource utilization, and (iii) impact of TCP on throughput performance over wireless networks. We further propose four novel mechanisms to improve the end-to-end application and wireless system performance: (i) an enhanced LTE uplink resource allocation mechanism to reduce network delay and help prevent a TCP timeout, (ii) a new TCP snooping mechanism, which according to our experiments, can save about 20% of system resources by preventing unnecessary video packet transmission through the air interface, and (iii) two Split-TCP protocols: an Enhanced Split-TCP (ES-TCP) and an Advanced Split-TCP (AS-TCP), which significantly improve the application throughput without breaking the end-to-end TCP semantics. Experimental results show that the proposed ES-TCP and AS-TCP protocols can boost the TCP throughput by more than 60% in average, when exercised over a 4G LTE network. Furthermore, the TCP throughput performance improvement may be even superior to 200%, depending on network and usage conditions. We expect that these proposed Split-TCP protocol enhancements, together with the new uplink resource allocation enhancement and the new TCP snooping mechanism may provide even greater performance gains when more advanced radio technologies, such as 5G, are deployed. Thanks to their superior resource utilization efficiency, such advanced radio technologies will put to greater use the techniques and protocol enhancements disclosed through this dissertation.

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 Advanced Wired and Wireless Networks written by Tadeusz A. Wysocki and published by Springer Science & Business Media. This book was released on 2005-12-17 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Wired and Wireless Networks brings the reader a sample of recent research efforts representative of advances in the areas of recognized importance for the future Internet, such as ad hoc networking, mobility support and performance improvements in advanced networks and protocols. Advanced Wired and Wireless Networks is structured to meet the needs of a professional audience in industry, as well as graduate-level students in computer science and engineering.

Download or read book Performance Analysis and Enhancement for IEEE 802 11e Wireless Networks written by 張緯康 and published by . This book was released on 2006 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book MAC layer Approaches for Security and Performance Enhancement in IEEE 802 11 written by Hao-Li Wang and published by . This book was released on 2004 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few years, wireless networks have become increasingly popular. The dominant question facing the wireless network today is: how can the network meet the needs of various users and applications? Two basic and primary needs for users are efficiency and security. To deal with these two concerns, this dissertation investigates the two areas and proposes four MAC-level approaches for security and performance enhancement in IEEE 802.11. In the first part, we propose three MAC-level approaches to improve the throughput performance in wireless LANs, i.e., the Freeze Counter scheme (FC), the Dynamically Adaptive Retransmission (DAR), and the Quick Acknowledgement (QA) scheme. The Freeze Counter scheme is an adaptive error recovery mechanism in 802.11 which can perform different actions according to the reasons for frame losses. Dynamically Adaptive Retransmission scheme is an enhanced feedback scheme in 802.11. We propose a Quick Acknowledgement (QA) scheme as a replacement for positive acknowledgement in IEEE 802.11. By using similar concepts as selective ACK and negative ACK, the proposed protocol solves the inefficiency problem of positive ACK in 802.11. In the second part, we propose a lightweight statistical authentication protocol for wireless networks. With more and more applications on wireless networks, new concerns are raised when it comes to security issues. Authentication service particularly becomes one of the basic but necessary security measures for wireless applications; however, traditional authentication protocols for wired networks do not work well in a wireless environment due to unique characteristics. To meet this target, we propose a lightweight statistical authentication protocol for wireless networks, namely Shepherd. To solve the inherent out-of-sync problem with Shepherd protocol, we develop three synchronization schemes with their statistical methods. In Shepherd, the legitimacy of a mobile node is determined by continuously checking a series of random authentication bits where each bit in this stream is piggybacked by a packet. Such an authentication bit stream is generated by both mobile node and access point using the same random number generator under the same shared seed as a key. The complete evaluation and analysis of all proposed approaches have been discussed.