Mobile Ad hoc Networking: Imperatives and Challenges

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, "ad-hoc" network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET\u27s characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

Improving forwarding mechanisms for mobile personal area networks

This thesis presents novel methods for improving forwarding mechanisms for personal area networks. Personal area networks are formed by interconnecting personal devices such as personal digital assistants, portable multimedia devices, digital cameras and laptop computers, in an ad hoc fashion. These devices are typically characterised by low complexity hardware, low memory and are usually batterypowered. Protocols and mechanisms developed for general ad hoc networking cannot be directly applied to personal area networks as they are not optimised to suit their specific constraints. The work presented herein proposes solutions for improving error control and routing over personal area networks, which are very important ingredients to the good functioning of the network. The proposed Packet Error Correction (PEC) technique resends only a subset of the transmitted packets, thereby reducing the overhead, while ensuring improved error rates. PEC adapts the number of re-transmissible packets to the conditions of the channel so that unnecessary retransmissions are avoided. It is shown by means of computer simulation that PEC behaves better, in terms of error reduction and overhead, than traditional error control mechanisms, which means that it is adequate for low-power personal devices. The proposed C2HR routing protocol, on the other hand, is designed such that the network lifetime is maximised. This is achieved by forwarding packets through the most energy efficient paths. C2HR is a hybrid routing protocol in the sense that it employs table-driven (proactive) as well as on-demand (reactive) components. Proactive routes are the primary routes, i.e., packets are forwarded through those paths when the network is stable; however, in case of failures, the protocol searches for alternative routes on-demand, through which data is routed temporarily. The advantage of C2HR is that data can still be forwarded even when routing is re-converging, thereby increasing the throughput. Simulation results show that the proposed routing method is more energy efficient than traditional least hops routing, and results in higher data throughput. C2HR relies on a network leader for collecting and distributing topology information, which in turn requires an estimate of the underlying topology. Thus, this thesis also proposes a new cooperative leader election algorithm and techniques for estimating network characteristics in mobile environments. The proposed solutions are simulated under various conditions and demonstrate appreciable behaviour

Design of rate-adaptive MAC and medium aware routing protocols for multi-rate, multi-hop wireless networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The IEEE 802.11 standard conformant wireless communication stations have multi-rate transmission capability. To achieve greater communication efficiency, multi-rate capable stations use rateadaptation to select appropriate transmission rate according to variations in the channel quality. The thesis presents two rate-adaptation schemes, each belonging to one of the two classes of rateadaptation schemes i.e.(1) the frame-transmission statistics based schemes, and (2) Signal-to-Noise Ratio (SNR) based, closed loop schemes. The SNR-based rate-adaptation scheme, proposed in this thesis uses a novel mechanism of delivering a receiver’s feedback to a transmitter; without requiring any modification in the standard frames as suggested by existing research. The frame-transmissionstatistics based rate adaptation solution uses an on-demand incremental strategy for selecting a rate-selection threshold. This solution is based on a cross-layer communication framework, where the rate-adaptation module uses information to/from the Application layer along with relevant information from the Medium Access Control (MAC) sub-layer. The proposed solutions are highly responsive when compared with existing rate-adaptation schemes; responsiveness is one of the key factors in the design of such protocols. The novel feedback mechanism makes it possible to achieve frame-loss differentiation with just three frames, avoiding the use of Request To Send/ Clear To Send (RTS/CTS) frames and further delays in this process. Performance tests have affirmed that the proposed rate-adaptation schemes are energy efficient; with efficiency up to 19% in specific test scenarios. In terms of throughput and frame loss-differentiation mechanisms, the proposed schemes have shown significantly better performance.Routing protocols for Mobile Ad-Hoc Networks (MANETs) use broadcast frames during the route discovery process. The 802.11 mandates the use of different transmission rates for broadcast and unicast (data-) frames. In many cases it causes creation of communication gray zones, where stations which are marked as ‘reachable neighbours’ using the broadcast frames (using lower transmission rate) are not accessible during normal, unicast communication (mainly at a higher rate). Similarly, higher device density, interference and mobility cause variable medium access delays. The IEEE 802.11e introduces four different MAC level queues for four access categories, maintaining service priority within the queues; which implies that frames from a higher priority queue are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result these factors are not considered which result in severe performance deterioration. To meet such challenges, the thesis presents a medium aware distance vector (MADV) routing protocol for MANETs. MADV uses MAC and physical layer (PHY) specific information in the route metric and maintains a separate route per-AC-per-destination in its routing tables. The MADV-metric can be incorporated into various routing rotocols and its applicability is determined by the possibility of provision of MAC dependent arameters that are used to determine the hop-by-hop MADV-metric values. Simulation tests and omparison with existing MANET protocols demonstrate the effectiveness of incorporating the medium dependent parameters and show that MADV is significantly better in terms of end-to-end delay and throughput

Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work

Performance evaluation of a prototyped wireless ground sensor networks

This thesis investigated the suitability of wireless, unattended ground sensor networks for military applications. The unattended aspect requires the network to self-organize and adapt to dynamic changes. A wireless, unattended ground sensor network was prototyped using commercial off-the-shelf technology and three to four networked nodes. Device and network performance were measured under indoor and outdoor scenarios. The measured communication range of a node varied between three and nineteen meters depending on the scenario. The sensors evaluated were an acoustic sensor, a magnetic sensor, and an acceleration sensor. The measured sensing range varied by the type of sensor. Node discovery durations observed were between forty seconds and over five minutes. Node density calculations indicated that the prototype was scalable to five hundred nodes. This thesis substantiated the feasibility of interconnecting, self-organizing sensor nodes in military applications. Tests and evaluations demonstrated that the network was capable of dynamic adaptation to failure and degradation.http://archive.org/details/performanceevalu109452263Approved for public release; distribution is unlimited

Integrated Framework For Mobile Low Power IoT Devices

Ubiquitous object networking has sparked the concept of the Internet of Things (IoT) which defines a new era in the world of networking. The IoT principle can be addressed as one of the important strategic technologies that will positively influence the humans’ life. All the gadgets, appliances and sensors around the world will be connected together to form a smart environment, where all the entities that connected to the Internet can seamlessly share data and resources. The IoT vision allows the embedded devices, e.g. sensor nodes, to be IP-enabled nodes and interconnect with the Internet. The demand for such technique is to make these embedded nodes act as IP-based devices that communicate directly with other IP networks without unnecessary overhead and to feasibly utilize the existing infrastructure built for the Internet. In addition, controlling and monitoring these nodes is maintainable through exploiting the existed tools that already have been developed for the Internet. Exchanging the sensory measurements through the Internet with several end points in the world facilitates achieving the concept of smart environment. Realization of IoT concept needs to be addressed by standardization efforts that will shape the infrastructure of the networks. This has been achieved through the IEEE 802.15.4, 6LoWPAN and IPv6 standards. The bright side of this new technology is faced by several implications since the IoT introduces a new class of security issues, such as each node within the network is considered as a point of vulnerability where an attacker can utilize to add malicious code via accessing the nodes through the Internet or by compromising a node. On the other hand, several IoT applications comprise mobile nodes that is in turn brings new challenges to the research community due to the effect of the node mobility on the network management and performance. Another defect that degrades the network performance is the initialization stage after the node deployment step by which the nodes will be organized into the network. The recent IEEE 802.15.4 has several structural drawbacks that need to be optimized in order to efficiently fulfil the requirements of low power mobile IoT devices. This thesis addresses the aforementioned three issues, network initialization, node mobility and security management. In addition, the related literature is examined to define the set of current issues and to define the set of objectives based upon this. The first contribution is defining a new strategy to initialize the nodes into the network based on the IEEE 802.15.4 standard. A novel mesh-under cluster-based approach is proposed and implemented that efficiently initializes the nodes into clusters and achieves three objectives: low initialization cost, shortest path to the sink node, low operational cost (data forwarding). The second contribution is investigating the mobility issue within the IoT media access control (MAC) infrastructure and determining the related problems and requirements. Based on this, a novel mobility scheme is presented that facilitates node movement inside the network under the IEEE 802.15.4e time slotted channel hopping (TSCH) mode. The proposed model mitigates the problem of frequency channel hopping and slotframe issue in the TSCH mode. The next contribution in this thesis is determining the mobility impact on low latency deterministic (LLDN) network. One of the significant issues of mobility is increasing the latency and degrading packet delivery ratio (PDR). Accordingly, a novel mobility protocol is presented to tackle the mobility issue in LLDN mode and to improve network performance and lessen impact of node movement. The final contribution in this thesis is devising a new key bootstrapping scheme that fits both IEEE 802.15.4 and 6LoWPAN neighbour discovery architectures. The proposed scheme permits a group of nodes to establish the required link keys without excessive communication/computational overhead. Additionally, the scheme supports the mobile node association process by ensuring secure access control to the network and validates mobile node authenticity in order to eliminate any malicious node association. The purposed key management scheme facilitates the replacement of outdated master network keys and release the required master key in a secure manner. Finally, a modified IEEE 802.15.4 link-layer security structure is presented. The modified architecture minimizes both energy consumption and latency incurred through providing authentication/confidentiality services via the IEEE 802.15.4

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms