The Simulation, Modeling and Analysis of Wireless Local Area Networks Supporting the IEEE 802. 11 Standard


Book Description

Research to improve the performance of the IEEE 802.11 has been ongoing since 1990. The focus of this research has investigated the use of the MAC and Physical layers for improving throughput. An adaptive MAC protocol, CATER (Code Adapts To Enhance Reliability) is based on the proposed MAC standard for wireless local area networks (WLAN)-802. 11. IEEE 802.11 uses a fixed Pseudo-Noise (PN) code for spreading the information signal, implying a fixed process gain at the receiver. When the channel degrades, IEEE 802.11 offers only retransmissions at the MAC layer to contend with the corrupted medium. However, CATER allows communicating stations to reconfigure their transceivers to use a longer PN code after a prescribed number of failed retransmissions. The longer PN code increases the process gain of the receiver and reduces the error rate. This thesis analyzes the performance of CATER as changing the factor: Start (the number of transmission before the channel is reconfigured) and Max (additional frame transmissions during reconfigure), PN code length, the number of station, and implementing Forward Error Correction (FEC). CATER provides better throughput for smaller Start and larger Max at a high bit error rate (10-3). When CATER uses a PN code length of 63, the throughput is increased by 101 percent at high bit error rate (BER). However, 802.11 is better than CATER at low BER ( 10-3).




Performance Analysis of Multi-Channel and Multi-Traffic on Wireless Communication Networks


Book Description

With the rapidly increasing penetration of laptop computers and mobile phones, which are primarily used by mobile users to access Internet s- vices like e-mail and World Wide Web (WWW) access, support of Internet services in a mobile environment is an emerging requirement. Wireless n- works have been used for communication among fully distributed users in a multimedia environment that has the needs to provide real-time bursty traffic (such as voice or video) and data traffic with excellent reliability and service quality. To satisfy the huge wireless multimedia service demand and improve the system performance, efficient channel access methods and analytical methods must be provided. In this way very accurate models, that faithfully reproduce the stochastic behavior of multimedia wireless communication and computer networks, can be constructed. Most of these system models are discrete-time queueing systems. Queueing networks and Markov chains are commonly used for the p- formance and reliability evaluation of computer, communication, and m- ufacturing systems. Although there are quite a few books on the individual topics of queueing networks and Markov chains, we have found none that covers the topics of discrete-time and continuous-time multichannel mul- traffic queueing networks. On the other hand, the design and development of multichannel mul- hop network systems and interconnected network systems or integrated n- works of multimedia traffic require not only such average performance m- sures as the throughput or packet delay but also higher moments of traffic departures and transmission delay.




Performance Modelling and Evaluation of Heterogeneous Wired


Book Description

Computer networks can be classified into two broad categories: wired networks and wireless networks, according to the hardware and software technologies used to interconnect the individual devices. Wired interconnection networks are hardware fabrics supporting communications between individual processors in highperformance computing systems (e.g., multi-computer systems and cluster systems). On the other hand, due to the rapid development of wireless technologies, wireless networks have emerged and become an indispensable part for people's lives. The integration of different wireless technologies is an effective approach to accommodate the increasing demand of the users to communicate with each other and access the Internet. This thesis aims to investigate the performance of wired interconnection networks and integrated wireless networks under the realistic working conditions. Traffic patterns have a significant impact on network performance. A number of recent measurement studies have convincingly demonstrated that the traffic generated by many real-world applications in communication networks exhibits bursty arrival nature and the message destinations are non-uniformly distributed. Analytical models for the performance evaluation of wired interconnection networks and integrated wireless networks have been widely reported. However, most of these models are developed under the simplified assumption of non-bursty Poisson process with uniformly distributed message destinations. To fill this gap, this thesis first presents an analytical model to investigate the performance of wired interconnection networks in multi-computer systems. Secondly, the analytical models for wired interconnection networks in multi-cluster systems are developed. Finally, this thesis proposes analytical models to evaluate the end-to-end delay and throughput of integrated wireless local area networks and wireless mesh networks. These models are derived when the networks are subject to bursty traffic with non-uniformly distributed message destinations which can capture the burstiness of real-world network traffic in the both temporal domain and spatial domain. Extensive simulation experiments are conducted to validate the accuracy of the analytical models. The models are then used as practical and cost-effective tools to investigate the performance of heterogeneous wired or wireless networks under the traffic patterns exhibited by real-world applications.







Improving the Performance of Wireless LANs


Book Description

While there are countless books on wireless networks, few actually quantify the key performance-limiting factors of wireless local area networks (WLANs) and describe various methods for improving WLAN performance. Fulfilling these needs, Improving the Performance of Wireless LANs: A Practical Guide provides both theoretical background and empirical results for the optimum planning and deployment of high performance WLAN systems in different residential and commercial buildings. Useful to students, faculties, researchers, engineers, and network developers, this must-have book not only explains the fundamentals of WLAN systems, including WLAN features and standards, but also: Supplies strategic guidelines for WLAN system design, modeling, and performance evaluation Includes radio propagation and site measurements as well as simulations for various network design scenarios Discusses environmental effects on WLAN performance, protocol redesign for routing and MAC, and traffic distribution Contains numerous illustrations and examples, plus chapter summaries, review questions, reading lists, mini-projects, an extensive glossary, and a list of acronyms Examines emerging and future network technologies, such as next generation Wi-Fi (802.11ac), very high throughput Wi-Fi (802.11ad), wireless mesh networking (802.11s), emergency QoS (802.11u), and vehicle-to-vehicle communications (802.11p) Improving the Performance of Wireless LANs: A Practical Guide makes the teaching, learning, and researching of advanced wireless network design and performance a more active process by using practical tools and exercises to add life to this highly technical subject.




Advances in Wireless Networks


Book Description

Recent years have witnessed tremendous growth in the population of mobile users demanding high performance, reliability and quality-of-service (QoS). Wireless networks are undergoing rapid developments and dramatic changes in the underlying technologies, in order to cope with the difficulties posed by the scarce wireless resource as well as keep up with the increasing day-to-day demand for cost-effective service of multimedia applications. Predicting and optimising the performance and QoS of wireless networks using analytical modelling, simulation experiments, monitoring and testbed-based measurements are crucial to the proper design, tuning, resource management and capacity planning of such networks. This book is dedicated to review important developments and results, explore recent state-of-the-art research and discuss new strategies for performance modelling, analysis and enhancement of wireless networks. The objective is to make analytical modelling, simulation and measurement tools, and innovative performance evaluation methodology possible and understandable to a wider audience.




Performance Modeling and Analysis of Bluetooth Networks


Book Description

Until now, developers and researchers interested in the design, operation, and performance of Bluetooth networks have lacked guidance about potential answers and the relative advantages and disadvantages of performance solutions. Performance Modeling and Analysis of Bluetooth Networks: Polling, Scheduling, and Traffic Control summarizes t




Improving the Performance of Wireless LANs


Book Description

While there are countless books on wireless networks, few actually quantify the key performance-limiting factors of wireless local area networks (WLANs) and describe various methods for improving WLAN performance. Fulfilling these needs, Improving the Performance of Wireless LANs: A Practical Guide provides both theoretical background and empirical