Cross Layer Design And Analysis For Mobile Ad Hoc Networks

Then, we design a MAC protocol for mobile ad hoc networks using directional antennas along with some further improvements. Besides, we also propose a coupled MAC and routing cross-layer design for ad hoc networks with power control. Furthermore, we look into the use of multiple channels in wireless mesh networks by carrying out real experiments on our testbeds, and provide some guidelines for using multi-channel in WMNs.

With the advances in wireless technologies and proliferation of mobile devices, ad hoc networks will play a significant role in enabling future ubiquitous communications. Despite the convenience of forming networks on the fly, without any pre-existing infrastructure, ad hoc networks suffer from serious security concerns. Security in ad hoc networks is challenging due to shared wireless medium, lack of fixed infrastructure, dynamic network topology and resource constrained users. Owing to these differences, conventional security measures used in wired networks are not suitable for wireless networks. To allow interoperability with other IP based networks such as Internet and 3G, existing wireless networks are built on the foundation of OSI and TCP/IP protocol suite.^However, the evolving wireless systems seriously question the traditional networking paradigm as these protocol stacks which are architected and implemented in a layered manner are not sufficiently flexible to cope with the dynamics in wireless environments. Cross-layer design has received considerable attention in recent years as the alternative networking paradigm for wireless networks. Through interactions and information exchange among protocol layers, these designs can create wireless architectures with better holistic views of network goals and constraints. The main goal of this dissertation is to design and develop efficient cross-layer architectures and techniques to enhance security and reliability in wireless ad hoc networks. In the first part of the thesis, we examine various cross-layer architectures to analyze their efficiency in detecting network anomalies.^Simulation studies indicate that cross-layer design based on a shared database model has higher system stability and lower overhead. Using this design, we developed CIDS, a cross-layer based intrusion detection system with an objective to provide accurate and reliable misbehavior detection in ad hoc networks. Using multiple linear regression analysis we study the correlation between different variables impacting network performance. This framework helps to identify the cause of a network anomaly and exploits the inter layer interactions to distinguish attacks from genuine network disruptions. In the second part of the thesis, we leverage the benefits of cross-layer interactions to provide defense against Denial of Service (DoS) attacks. We model jamming attacks at the physical and MAC layers to study DoS behavior, and analyze their impact on network throughput.^We develop a cross-layer based measurement driven approach where congestion estimation using physical, MAC and network layer information is used to differentiate jamming and congested scenarios for reliable classification of attacks. Next, we provide a game theoretic framework to formulate jamming as a non cooperative Bayesian game to analyze the interaction between attacker and monitor nodes. We develop hybrid energy efficient detection strategies at the monitor using cross-layer features to achieve the balance in security-energy tradeoff. By estimating the game state, we derive optimal attack and detection strategies. Finally, we show that the benefits of cross-layer interactions can be extended to security in wireless sensor networks. Tailoring to the needs of the environment, we develop a distributed security architecture (XLSEC) using cross-layer adaptations for layered ZigBee protocol stack targeted towards sensor networks.^Here, we incorporate cross-layer interactions within the node as well as among other nodes in the network. In addition, we demonstrate that cross-layer based learning techniques can be used to detect anomalies by correlating the information collected by each sensor node at different protocol layers in a machine learning anomaly detection framework (MALADY).

Mobile Ad Hoc Networks (MANETs) are gaining increasing popularity in recent years because of their ease of deployment. They are distributed, dynamic, and self-configurable without infrastructure support. Routing in ad hoc networks is a challenging task because of the MANET dynamic nature. Hence, researchers were focused in designing best-effort distributed and dynamic routing protocols to ensure optimum network operations in an unpredictable wireless environment. Nowadays, there is an increased demand on multimedia applications (stringent delay and reliability requirements), which makes a shift from best-effort services to Quality of Services. Actually, the challenge in wireless ad hoc networks is that neighbor nodes share the same channel and they take part in forwarding packets. Therefore, the total effective channel capacity is not only limited by the raw channel capacity but is also limited by the interactions and interferences among neighboring nodes. Thus, such factors should be taken in consideration in order to offer QoS routing. While, some of the distributed QoS route selection algorithms assume the availability of such information, others propose mechanisms to estimate them. The goals of this thesis are: (i) to analyze the performance of IEEE 802.11 MAC mechanism in non-saturation conditions, (ii) to use the analysis in the context of multi-hop ad hoc networks, (iii) to derive theoretical limits for nodes performance in multi-hop ad hoc networks, (iv) to use the multi-hop analysis in QoS route selection. We start the thesis by proposing a discrete-time 3D Markov chain model to analyze the saturation performance of the RTS/CTS access mode. This model integrates the backoff countdown process, retransmission retry limits, and transmission errors into one model. The impact of system parameters (e.g., number of nodes, packet size, retry limits, and BERs) are analyzed. Next, we extend the 3D model to analyze the performance under non-saturation conditions and finite buffer capacity using two different approaches. First, we extend the 3D model into a 4D model to integrate the transmission buffer behavior. Second, we replace the 4D model by an M/G/1/K queueing system model with independent samples from the saturation analysis. The latter model gives similar results as the former but with a reduction in the analysis complexity. Next and by means of the non-saturation analysis, we proposed an approximate mathematical model for multi-hop ad hoc networks. Furthermore, we proposed an iterative mechanism to estimate the throughput in the presence of multiple flows. Finally, we used the multi-hop analysis to propose a QoS route selection algorithm. In this algorithm, we concentrate on the throughput as a QoS parameter. However, the proposed algorithm is valid to be used with other QoS parameters, such as packet delay, packet loss probability, and fairness. Analytical and simulation results show the deficiency of the current route selection algorithm in AODV and at the same time verifies the need for QoS route selection algorithms.

Information flow in a telecommunication network is accomplished through the interaction of mechanisms at various design layers with the end goal of supporting the information exchange needs of the applications. In wireless networks in particular, the different layers interact in a nontrivial manner in order to support information transfer. In this text we will present abstract models that capture the cross-layer interaction from the physical to transport layer in wireless network architectures including cellular, ad-hoc and sensor networks as well as hybrid wireless-wireline. The model allows for arbitrary network topologies as well as traffic forwarding modes, including datagrams and virtual circuits. Furthermore the time varying nature of a wireless network, due either to fading channels or to changing connectivity due to mobility, is adequately captured in our model to allow for state dependent network control policies. Quantitative performance measures that capture the quality of service requirements in these systems depending on the supported applications are discussed, including throughput maximization, energy consumption minimization, rate utility function maximization as well as general performance functionals. Cross-layer control algorithms with optimal or suboptimal performance with respect to the above measures are presented and analyzed. A detailed exposition of the related analysis and design techniques is provided.

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.

This book presents the tutorial lectures given by leading experts in the area at the IFIP WG 7.3 International Symposium on Computer Modeling, Measurement and Evaluation, Performance 2002, held in Rome, Italy in September 2002.The survey papers presented are devoted to theoretical and methodological advances in performance and reliability evaluation as well as new perspectives in the major application fields. Modeling and verification issues, solution methods, workload characterization, and benchmarking are addressed from the methodological point of view. Among the applications dealt with are hardware and software architectures, wired and wireless networks, grid environments, Web services, and real-time voice and video processing.This book is intended to serve as a state-of-the-art survey and reference for students, scientists, and engineers active in the area of performance and reliability evaluation.