A Survey on Wireless Ad Hoc Networks
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paper_title: Floor acquisition multiple access (FAMA) for packet-radio networks

paper_content:

A family of medium access control protocols for single-channel packet radio networks is specified and analyzed. These protocols are based on a new channel access discipline called floor acquisition multiple access (FAMA), which consists of both carrier sensing and a collision-avoidance dialogue between a source and the intended receiver of a packet. Control of the channel (the floor) is assigned to at most one station in the network at any given time, and this station is guaranteed to be able to transmit one or more data packets to different destinations with no collision with transmissions from other stations. The minimum length needed in control packets to acquire the floor is specified as a function of the channel propagation time. The medium access collision avoidance (MACA) protocol proposed by Karn and variants of CSMA based on collision avoidance are shown to be variants of FAMA protocols when control packets last long enough compared to the channel propagation delay. The throughput of FAMA protocols is analyzed and compared with the throughput of non-persistent CSMA. This analysis shows that using carrier sensing as an integral part of the floor acquisition strategy provides the benefits of MACA in the presence of hidden terminals, and can provide a throughput comparable to, or better than, that of non-persistent CSMA when no hidden terminals exist.
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paper_title: Mobile Ad Hoc Networking: Imperatives and Challenges

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A mobile ad hoc network (MANET), sometimes called a mobile mesh network, is a self- configuring network of mobile devices connected by wireless links. The Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. It 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. 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 adhoc 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.So,we would like to propose the challenges and imperativels that the MANET is facing.
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paper_title: Medium Access Control protocols for ad hoc wireless networks : A survey

paper_content:

Studies of ad hoc wireless networks are a relatively new field gaining more popularity for various new applications. In these networks, the Medium Access Control (MAC) protocols are responsible for coordinating the access from active nodes. These protocols are of significant importance since the wireless communication channel is inherently prone to errors and unique problems such as the hidden-terminal problem, the exposed-terminal problem, and signal fading effects. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation of each other. We therefore make an attempt to present a comprehensive survey of major schemes, integrating various related issues and challenges with a view to providing a big-picture outlook to this vast area. We present a classification of MAC protocols and their brief description, based on their operating principles and underlying features. In conclusion, we present a brief summary of key ideas and a general direction for future work.
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paper_title: MACAW: a media access protocol for wireless LAN's

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In recent years, a wide variety of mobile computing devices has emerged, including portables, palmtops, and personal digital assistants. Providing adequate network connectivity for these devices will require a new generation of wireless LAN technology. In this paper we study media access protocols for a single channel wireless LAN being developed at Xerox Corporation's Palo Alto Research Center. We start with the MACA media access protocol first proposed by Karn [9] and later refined by Biba [3] which uses an RTS-CTS-DATA packet exchange and binary exponential back-off. Using packet-level simulations, we examine various performance and design issues in such protocols. Our analysis leads to a new protocol, MACAW, which uses an RTS-CTS-DS-DATA-ACK message exchange and includes a significantly different backoff algorithm.
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paper_title: Wireless medium access control protocols

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Technological advances, coupled with the flexibility and mobility of wireless systems, are the driving force behind the Anyone, Anywhere, Anytime paradigm of networking. At the same time, we see a convergence of the telephone, cable and data networks into a unified network that supports multimedia and real-time applications like voice and video in addition to data. Medium access control protocols define rules for orderly access to the shared medium and play a crucial role in the efficient and fair sharing of scarce wireless bandwidth. The nature of the wireless channel brings new issues like location-dependent carrier sensing, time varying channel and burst errors. Low power requirements and half duplex operation of the wireless systems add to the challenge. Wireless MAC protocols have been heavily researched and a plethora of protocols have been proposed. Protocols have been devised for different types of architectures, different applications and different media. This survey discusses the challenges in the design of wireless MAC protocols, classifies them based on architecture and mode of operation, and describes their relative performance and application domains in which they are best deployed.
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paper_title: Receiver-initiated busy-tone multiple access in packet radio networks

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The ALOHA and Carrier Sense Multiple Access (CSMA) protocols have been proposed for packet radio networks (PRN). However, CSMA/CD which gives superior performance and has been successful applied in local area networks cannot be readily applied in PRN since the locally generated signals will overwhelm a remote transmission, rendering it impossible to tell whether a collision has occurred or not. In addition, CSMA and CSMA/CD suffer from the “hidden node” problem in a multihop PRN. In this paper, we develop the Receiver-Initiated Busy-Tone Multiple Access Protocol to resolve these difficulties. Both fully connected and multihop networks are studied. The busy tone serves as an acknowledgement and prevents conflicting transmissions from other nodes, including “hidden nodes”.
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paper_title: Hop-reservation multiple access (HRMA) for ad-hoc networks

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A new multichannel MAC protocol called hop-reservation multiple access (HRMA) for wireless ad-hoc networks (multi-hop packet radio networks) is introduced, specified and analyzed. HRMA is based on simple half-duplex, very slow frequency-hopping spread spectrum (FHSS) radios and takes advantage of the time synchronization necessary for frequency-hopping. HRMA allows a pair of communicating nodes to reserve a frequency hop using a reservation and handshake mechanism that guarantee collision-free data transmission in the presence of hidden terminals. We analyze the throughput achieved in HRMA for the case of a hypercube network topology assuming variable-length packets, and compare it against the multichannel slotted ALOHA protocol, which represents the current practice of MAC protocols in commercial ad-hoc networks based on spread spectrum radios, such as Metricom's Ricochet system. The numerical results show that HRMA can achieve much higher throughput than multichannel slotted ALOHA within the traffic-load ranges of interest, especially when the average packet length is large compared to the duration of a dwell time in the frequency hopping sequence, in which case the maximum throughput of HRMA is close to the maximum possible value.
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paper_title: Dual Busy Tone Multiple Access (DBTMA) - A Multiple Access Control Scheme for Ad Hoc Networks

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In ad hoc networks, the hidden- and the exposed-terminal problems can severely reduce the network capacity on the MAC layer. To address these problems, the ready-to-send and clear-to-send (RTS/CTS) dialogue has been proposed in the literature. However, MAC schemes using only the RTS/CTS dialogue cannot completely solve the hidden and the exposed terminal problems, as pure "packet sensing" MAC schemes are not safe even in fully connected networks. We propose a new MAC protocol, termed the dual busy tone multiple access (DBTMA) scheme. The operation of the DBTMA protocol is based on the RTS packet and two narrow-bandwidth, out-of-band busy tones. With the use of the RTS packet and the receive busy tone, which is set up by the receiver, our scheme completely solves the hidden- and the exposed-terminal problems. The busy tone, which is set up by the transmitter, provides protection for the RTS packets, increasing the probability of successful RTS reception and, consequently, increasing the throughput. This paper outlines the operation rules of the DBTMA scheme and analyzes its performance. Simulation results are also provided to support the analytical results. It is concluded that the DBTMA protocol is superior to other schemes that rely on the RTS/CTS dialogue on a single channel or to those that rely on a single busy tone. As a point of reference, the DBTMA scheme out-performs FAMA-NCS by 20-40% in our simulations using the network topologies borrowed from the FAMA-NCS paper. In an ad hoc network with a large coverage area, DBTMA achieves performance gain of 140% over FAMA-NCS and performance gain of 20% over RI-BTMA.
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paper_title: A multichannel CSMA MAC protocol for multihop wireless networks

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We describe a new carrier-sense multiple access (CSMA) protocol for multihop wireless networks, sometimes also called ad hoc networks. The CSMA protocol divides the available bandwidth into several channels and selects an idle channel randomly for packet transmission. It also employs a notion of "soft" channel reservation as it gives preference to the channel that was used for the last successful transmission. We show via simulations that this multichannel CSMA protocol provides a higher throughput compared to its single channel counterpart by reducing the packet loss due to collisions. We also show that the use of channel reservation provides better performance than multichannel CSMA with purely random idle channel selection.
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paper_title: Architecture and algorithms for an IEEE 802.11-based multi-channel wireless mesh network

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Even though multiple non-overlapped channels exist in the 2.4 GHz and 5 GHz spectrum, most IEEE 802.11-based multi-hop ad hoc networks today use only a single channel. As a result, these networks rarely can fully exploit the aggregate bandwidth available in the radio spectrum provisioned by the standards. This prevents them from being used as an ISP's wireless last-mile access network or as a wireless enterprise backbone network. In this paper, we propose a multi-channel wireless mesh network (WMN) architecture (called Hyacinth) that equips each mesh network node with multiple 802.11 network interface cards (NICs). The central design issues of this multi-channel WMN architecture are channel assignment and routing. We show that intelligent channel assignment is critical to Hyacinth's performance, present distributed algorithms that utilize only local traffic load information to dynamically assign channels and to route packets, and compare their performance against a centralized algorithm that performs the same functions. Through an extensive simulation study, we show that even with just 2 NICs on each node, it is possible to improve the network throughput by a factor of 6 to 7 when compared with the conventional single-channel ad hoc network architecture. We also describe and evaluate a 9-node Hyacinth prototype that Is built using commodity PCs each equipped with two 802.11a NICs.
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paper_title: An energy efficient MAC protocol for wireless LANs

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This paper presents an optimization of the power saving mechanism in the Distributed Coordination Function (DCF) in the IEEE 802.11 standard. In the IEEE 802.11 power saving mode specified for DCF, time is divided into so-called beacon intervals. At the start of each beacon interval, each node in the power saving mode periodically wakes up for a duration called the ATIM window. The nodes are required to be synchronized to ensure that all nodes wake up at the same time. During the ATIM window, the nodes exchange control packets to determine whether they need to stay awake for the rest of the beacon interval. The size of the ATIM window has a significant impact on energy saving and throughput achieved by the nodes. This paper proposes an adaptive mechanism to dynamically choose a suitable ATIM window size. We also allow the nodes to stay awake for only a fraction of the beacon interval following the ATIM window. On the other hand, IEEE 802.11 DCF mode requires the nodes to stay awake either for the entire beacon interval following the ATIM window or none at all. Simulation results show that the proposed approach outperforms the IEEE 802.11 power saving mechanism in terms of throughput and the amount of energy consumed.
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paper_title: PAMAS—power aware multi-access protocol with signalling for ad hoc networks

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In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well.
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paper_title: A power control MAC protocol for ad hoc networks

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This paper presents a power control MAC protocol based on the IEEE 802.11 standard. Several researchers have proposed a simple modification of IEEE 802.11 to incorporate power control. The main idea of these power control schemes is to use different power levels for RTS-CTS and DATA-ACK. Specifically, maximum transmit power is used for RTS-CTS, and the minimum required transmit power is used for DATA-ACK transmissions in order to save energy. However, we show that this scheme can degrade network throughput and can result in higher energy consumption than using IEEE 802.11 without power control. We propose an improved power control protocol which does not degrade throughput and yields energy saving.
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paper_title: Analyzing the Energy Consumption of IEEE 802.11 Ad Hoc Networks

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This paper analyzes the energy consumption of ad hoc nodes using IEEE 802.11 interfaces. Our objective is to provide theoretical limits on the lifetime gains that can be achieved by different power saving techniques proposed in the literature. The evaluation takes into account the properties of the medium access protocol and the process of forwarding packets in ad hoc mode. The key point is to determine the node lifetime based on its average power consumption. The average power consumption is estimated considering how long the node remains sleeping, idle, receiving, or transmitting.
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paper_title: Medium Access Control protocols for ad hoc wireless networks : A survey

paper_content:

Studies of ad hoc wireless networks are a relatively new field gaining more popularity for various new applications. In these networks, the Medium Access Control (MAC) protocols are responsible for coordinating the access from active nodes. These protocols are of significant importance since the wireless communication channel is inherently prone to errors and unique problems such as the hidden-terminal problem, the exposed-terminal problem, and signal fading effects. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation of each other. We therefore make an attempt to present a comprehensive survey of major schemes, integrating various related issues and challenges with a view to providing a big-picture outlook to this vast area. We present a classification of MAC protocols and their brief description, based on their operating principles and underlying features. In conclusion, we present a brief summary of key ideas and a general direction for future work.
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paper_title: A power controlled multiple access protocol for wireless packet networks

paper_content:

Multiple access-based collision avoidance MAC protocols have typically used fixed transmission power, and have not considered power control mechanisms based on the distance of the transmitter and receiver in order to improve spatial channel reuse. This work proposes PCMA, a power controlled multiple access wireless MAC protocol within the collision avoidance framework. PCMA generalizes the transmit-or-defer "on/off" collision avoidance model of current protocols to a more flexible "variable bounded power" collision suppression model. The algorithm is provisioned for ad hoc networks and does not require the presence of base stations to manage transmission power (i.e. it is decentralized). The advantage of implementing a power controlled protocol in an ad-hoc network is that source-destination pairs can be more tightly packed into the network allowing a greater number of simultaneous transmissions (spectral reuse). Our initial simulation results show that the PCMA can improve the throughput performance of the non-power controlled IEEE 802.11 by a factor of 2 with potential for additional scalability as source-destination pairs become more localized, thus providing a compelling reason for migrating to a new power controlled multiple access wireless MAC protocol standard.
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paper_title: Adaptive Clustering for Mobile Wireless Networks

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This paper describes a self-organizing, multihop, mobile radio network which relies on a code-division access scheme for multimedia support. In the proposed network architecture, nodes are organized into nonoverlapping clusters. The clusters are independently controlled, and are dynamically reconfigured as the nodes move. This network architecture has three main advantages. First, it provides spatial reuse of the bandwidth due to node clustering. Second, bandwidth can be shared or reserved in a controlled fashion in each cluster. Finally, the cluster algorithm is robust in the face of topological changes caused by node motion, node failure, and node insertion/removal. Simulation shows that this architecture provides an efficient, stable infrastructure for the integration of different types of traffic in a dynamic radio network.
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paper_title: Multicluster, mobile, multimedia radio network

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A multi-cluster, multi-hop packet radio network architecture for wireless adaptive mobile information systems is presented. The proposed network supports multimedia traffic and relies on both time division and code division access schemes. This radio network is not supported by a wired infrastructure as conventional cellular systems are. Thus, it can be instantly deployed in areas with no infrastructure at all. By using a distributed clustering algorithm, nodes are organized into clusters. The clusterheads act as local coordinators to resolve channel scheduling, perform power measurement/control, maintain time division frame synchronization, and enhance the spatial reuse of time slots and codes. Moreover, to guarantee bandwidth for real time traffic, the architecture supports virtual circuits and allocates bandwidth to circuits at call setup time. The network is scalable to large numbers of nodes, and can handle mobility. Simulation experiments evaluate the performance of the proposed scheme in static and mobile environments.
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paper_title: INSIGNIA: IN-BAND SIGNALING SUPPORT FOR QOS IN MOBILE AD HOC NETWORKS

paper_content:

Vaporous alkylene oxides are polymerized by passage over catalysts at elevated temperatures. Alkaline catalysts, such as caustic potash, caustic soda and the oxides or hydroxides of the other alkali metals are suitable for the preparation of highly polymerized wax-like products, which may be liquid or solid, while acid-reacting substances, such as sodium bisulphate, aluminium sulphate, or mixtures of these with small amounts of sulphuric acid or with diluents such as sodium sulphate, or acid phosphates, are suitable catalysts for the preparation of dioxane and its homologues. The temperatures of working lie between 40 DEG -200 DEG C., the range 100-160 DEG C. being preferred. In the examples, (1) ethylene oxide vapour is led over anhydrous caustic soda at the rate of 0,1-0,4 gram per second per litre of catalyst, the catalyst being situated in a vertical iron tube which is maintained at 120-130 DEG C., this temperature regulation being effected by means of a jacket containing a suitable liquid, e.g. ethylene glycol. Cooling in the reaction chamber is also aided by the use of excess of ethylene oxide, which passes out at the lower end of the tube and is returned to the process. The liquid formed is collected in a closed receiver, where it solidifies to a waxy or horn-like mass. This may be freed from enclosed caustic potash by dissolving it in benzene, filtering and evaporating. (2) Anhydrous sodium bisulphate is substituted for the caustic soda of the previous example, and the ethylene oxide passed over it, the vapours condensed and returned to the process. After about 24 hours, the condensate is fractionated, yielding unchanged ethylene oxide, dioxane and a small amount of acetaldehyde ethylene acetal (3) Propylene oxide is passed over anhydrous potassium hydroxide as in example (1). The product is a viscous liquid which is insoluble in water but soluble in most organic solvents, including alcohol, ether, and aromatic hydrocarbons. (4) Propylene oxide is passed over a catalyst consisting of 1 part of sodium bisulphate mixed with 3 parts of anhydrous sodium sulphate. From the issuing vapours, a crude dimethyl dioxane consisting mainly of 2,5 dimethyl dioxane is condensed, distilled in vacuo under reduced pressure, then fractionally distilled.
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paper_title: SWAN: service differentiation in stateless wireless ad hoc networks

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We propose SWAN, a stateless network model which uses distributed control algorithms to deliver service differentiation in mobile wireless ad hoc networks in a simple, scalable and robust manner. We use rate control for UDP and TCP best-effort traffic, and sender-based admission control for UDP real-time traffic. SWAN uses explicit congestion notification (ECN) to dynamically regulate admitted real-time traffic in the face of network dynamics brought on by mobility or traffic overload conditions. We use the term "soft" real-time services to indicate that real-time sessions could be regulated or dropped due to mobility or excessive traffic overloading at mobile wireless routers. SWAN is designed to limit such conditions, however. A novel aspect of SWAN is that it does not require the support of a QOS-capable MAC. Rather, soft real-time services are built using existing best effort wireless MAC technology. Simulation, analysis, and results from an experimental wireless testbed show that real-time applications experience low and stable delays under various multi-hop, traffic and mobility conditions. The wireless testbed and ns-2 simulator source code are available from the Web (comet.columbia.edu/swan).
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paper_title: Soft reservation multiple access with priority assignment (SRMA/PA): a novel MAC protocol for QoS-guaranteed integrated services in mobile ad-hoc networks

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A new medium access control (MAC) protocol-soft reservation multiple access with priority assignment (SRMA/PA) protocol-is introduced for supporting the integrated services of real-time and non-real-time applications in mobile ad-hoc networks. The SRMA/PA protocol allows the distributed nodes to contend for and reserve time slots with a RTS/CTS-like "collision-avoidance" handshake and "soft reservation" mechanism augmented with distributed and dynamic access priority control, which virtually achieves capability of the distributed scheduling to guarantee the QoS requirements of the integrated services. We have demonstrated via simulation studies that the multiplexing gain can be significantly improved without much compromising the system complexity. We also have shown that the proposed back-off mechanism designed for the delay-constrained services is useful for further improving the channel utilization.
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paper_title: A flexible quality of service model for mobile ad-hoc networks

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Quality of service (QoS) support in mobile ad-hoc networks (MANETs) is a challenging task. Most of the proposals in the literature only address certain aspects of the QoS support, e.g., QoS routing, QoS medium access control (MAC) and resource reservation. However, none of them proposes a QoS model for MANETs. Meanwhile, two QoS models have been proposed for the Internet, viz., the integrated services (IntServ) model and the differentiated services (DiffServ) model, but these models are aimed for wired networks. In this paper, we propose a flexible QoS model for MANETs (FQMM) which considers the characteristics of MANETs and combines the high quality QoS of IntServ and service differentiation of Diff-Serv. Salient features of FQMM include: dynamics roles of nodes, hybrid provisioning and adaptive conditioning. Preliminary simulation results show that FQMM achieves better performance in terms of throughput and service differentiation than the best-effort model.
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paper_title: A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks

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An ad hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. In order to facilitate communication within the network, a routing protocol is used to discover routes between nodes. The primary goal of such an ad hoc network routing protocol is correct and efficient route establishment between a pair of nodes so that messages may be delivered in a timely manner. Route construction should be done with a minimum of overhead and bandwidth consumption. This article examines routing protocols for ad hoc networks and evaluates these protocols based on a given set of parameters. The article provides an overview of eight different protocols by presenting their characteristics and functionality, and then provides a comparison and discussion of their respective merits and drawbacks.
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paper_title: A review of routing protocols for mobile ad hoc networks

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Abstract The 1990s have seen a rapid growth of research interests in mobile ad hoc networking. The infrastructureless and the dynamic nature of these networks demands new set of networking strategies to be implemented in order to provide efficient end-to-end communication. This, along with the diverse application of these networks in many different scenarios such as battlefield and disaster recovery, have seen MANETs being researched by many different organisations and institutes. MANETs employ the traditional TCP/IP structure to provide end-to-end communication between nodes. However, due to their mobility and the limited resource in wireless networks, each layer in the TCP/IP model require redefinition or modifications to function efficiently in MANETs. One interesting research area in MANET is routing. Routing in the MANETs is a challenging task and has received a tremendous amount of attention from researches. This has led to development of many different routing protocols for MANETs, and each author of each proposed protocol argues that the strategy proposed provides an improvement over a number of different strategies considered in the literature for a given network scenario. Therefore, it is quite difficult to determine which protocols may perform best under a number of different network scenarios, such as increasing node density and traffic. In this paper, we provide an overview of a wide range of routing protocols proposed in the literature. We also provide a performance comparison of all routing protocols and suggest which protocols may perform best in large networks.
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paper_title: QoS for Ad hoc Networking Based on Multiple Metrics: Bandwidth and Delay.

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A link state routing approach makes available detailed information about the connectivity and the condition found in the network. OLSR protocol is an optimization over the classical link state protocol, tailored for mobile ad hoc networks. In this article, we design a QoS routing scheme over OLSR protocol, called QOLSR. In our proposal, we introduce more appropriate metrics than the hop distance used in OLSR. In order to improve quality requirements in routing information, delay and bandwidth measurements are applied. The implications of routing metrics on path computation are examined and the relational behind the selection of bandwidth and delay metrics are discussed. We first consider algorithms for single-metric approach, and then present a distributed algorithm for multiple metrics approach. We also present a scalable simulation model close to real operations in Ad Hoc Networks. The performance of our protocol are extensively investigated by simulation. Our results indicate that the attained gain by our proposal represent an important improvement in such mobile wireless networks.
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paper_title: Scalable Routing Protocols for Mobile Ad Hoc Networks

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The growing interest in mobile ad hoc network techniques has resulted in many routing protocol proposals. Scalability issues in ad hoc networks are attracting increasing attention these days. We survey the routing protocols that address scalability. The routing protocols included in the survey fall into three categories: flat routing protocols; hierarchical routing approaches; GPS augmented geographical routing schemes. The article compares the scalability properties and operational features of the protocols and discusses challenges in future routing protocol designs.
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paper_title: Reducing latency and overhead of route repair with controlled flooding

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Ad hoc routing protocols that use broadcast for route discovery may be inefficient if the path between any source-destination pair is frequently broken. We propose and evaluate a simple mechanism that allows fast route repair in on demand ad hoc routing protocols. We apply our proposal to the Ad hoc On-demand Distance Vector (AODV) routing protocol. The proposed system is based on the Controlled Flooding (CF) framework, where alternative routes are established around the main original path between source-destination pairs. With alternative routing, data packets are forwarded through a secondary path without requiring the source to re-flood the whole network, as may be the case in AODV. We are interested in one-level alternative routing. We show that our proposal reduces the connection disruption probability as well as the frequency of broadcasts.
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paper_title: Energy efficient routing in wireless ad hoc networks

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Ad hoc wireless networks are power constrained since nodes operate with limited battery energy. Thus, energy consumption is crucial in the design of new ad hoc routing protocols. To design such protocols, we have to look away from the traditional minimum, hop routing schemes. In this, paper, we propose three extensions to the state-of-the-art shortest-cost routing algorithm, AODV. The discovery mechanism in these extensions (LEAR-AODV, PAR-AODV, and LPR-AODV) uses energy consumption as a routing metric. They reduce the energy consumption of the nodes by routing packets to their destination using energy-optimal routes. We show that these algorithms improve the network survivability by maintaining the network connectivity. They carry out this objective with low overhead and without affecting the other wireless network protocol layers.
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paper_title: A Survey on Position-Based Routing in Mobile Ad-Hoc Networks

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We present an overview of ad hoc routing protocols that make forwarding decisions based on the geographical position of a packet's destination. Other than the destination's position, each node need know only its own position and the position of its one-hop neighbors in order to forward packets. Since it is not necessary to maintain explicit routes, position-based routing does scale well even if the network is highly dynamic. This is a major advantage in a mobile ad hoc network where the topology may change frequently. The main prerequisite for position-based routing is that a sender can obtain the current position of the destination. Therefore, previously proposed location services are discussed in addition to position-based packet forwarding strategies. We provide a qualitative comparison of the approaches in both areas and investigate opportunities for future research.
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paper_title: Optimized Link State Routing Protocol (OLSR)

paper_content:

This document describes the Optimized Link State Routing (OLSR) protocol for mobile ad hoc networks. The protocol is an optimization of the classical link state algorithm tailored to the requirements of a mobile wireless LAN. The key concept used in the protocol is that of multipoint relays (MPRs). MPRs are selected nodes which forward broadcast messages during the flooding process. This technique substantially reduces the message overhead as compared to a classical flooding mechanism, where every node retransmits each message when it receives the first copy of the message. In OLSR, link state information is generated only by nodes elected as MPRs. Thus, a second optimization is achieved by minimizing the number of control messages flooded in the network. As a third optimization, an MPR node may chose to report only links between itself and its MPR selectors. Hence, as contrary to the classic link state algorithm, partial link state information is distributed in the network. This information is then used for route calculation. OLSR provides optimal routes (in terms of number of hops). The protocol is particularly suitable for large and dense networks as the technique of MPRs works well in this context.
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paper_title: DSR : The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks

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The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. DSR allows the network to be completely self-organizing and self-configuring, without the need for any existing network infrastructure or administration. The protocol is composed of the two mechanisms of Route Discovery and Route Maintenance, which work together to allow nodes to discover and maintain source routes to arbitrary destinations in the ad hoc network. The use of source routing allows packet routing to be trivially loop-free, avoids the need for up-to-date routing information in the intermediate nodes through which packets are forwarded, and allows nodes forwarding or overhearing packets to cache the routing information in them for their own future use. All aspects of the protocol operate entirely on-demand, allowing the routing packet overhead of DSR to scale automatically to only that needed to react to changes in the routes currently in use. We have evaluated the operation of DSR through detailed simulation on a variety of movement and communication patterns, and through implementation and significant experimentation in a physical outdoor ad hoc networking testbed we have constructed in Pittsburgh, and have demonstrated the excellent performance of the protocol. In this chapter, we describe the design of DSR and provide a summary of some of our simulation and testbed implementation results for the protocol.
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paper_title: Reducing latency and overhead of route repair with controlled flooding

paper_content:

Ad hoc routing protocols that use broadcast for route discovery may be inefficient if the path between any source-destination pair is frequently broken. We propose and evaluate a simple mechanism that allows fast route repair in on demand ad hoc routing protocols. We apply our proposal to the Ad hoc On-demand Distance Vector (AODV) routing protocol. The proposed system is based on the Controlled Flooding (CF) framework, where alternative routes are established around the main original path between source-destination pairs. With alternative routing, data packets are forwarded through a secondary path without requiring the source to re-flood the whole network, as may be the case in AODV. We are interested in one-level alternative routing. We show that our proposal reduces the connection disruption probability as well as the frequency of broadcasts.
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paper_title: Highly dynamic Destination-Sequenced Distance-Vector routing (DSDV) for mobile computers

paper_content:

An ad-hoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such ad-hoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic Bellman-Ford routing mechanisms, as specified by RIP [5], to make it suitable for a dynamic and self-starting network mechanism as is required by users wishing to utilize ad hoc networks. Our modifications address some of the previous objections to the use of Bellman-Ford, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing the links between the Mobile Hosts. Finally, we describe the ways in which the basic network-layer routing can be modified to provide MAC-layer support for ad-hoc networks.
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paper_title: The Optimized Link State Routing Protocol Evaluation through Experiments and Simulation

paper_content:

In this paper, we describe the Optimized Link State Routing Protocol (OLSR) [1] for Mobile Ad-hoc NETworks (MANETs) and the evaluation of this protocol through experiments and simulations. In particular, we emphasize the practical tests and intensive simulations, which have been used in guiding and evaluating the design of the protocol, and which have been a key to identifying both problems and solutions. OLSR is a proactive link-state routing protocol, employing periodic message exchange for updating topological information in each node in the network. I.e. topological information is flooded to all nodes in the network. Conceptually, OLSR contains three elements: Mechanisms for neighbor sensing based on periodic exchange of HELLO messages within a node’s neighborhood. Generic mechanisms for efficient flooding of control traffic into the network employing the concept of multipoint relays (MPRs) [5] for a significant reduction of duplicate retransmissions during the flooding process. And a specification of a set of control-messages providing each node with sufficient topological information to be able to compute an optimal route to each destination in the network using any shortest-path algorithm. Experimental work, running a test-network of laptops with IEEE 802.11 wireless cards, revealed interesting properties. While the protocol, as originally specified, works quite well, it was found, that enforcing “jitter” on the interval between the periodic exchange of control messages in OLSR and piggybacking said control messages into a single packet, significantly reduced the number of messages lost due to collisions. It was also observed, that under certain conditions a “naive” neighbor sensing mechanism was insufficient: a bad link between two nodes (e.g. when two nodes are on the edge of radio range) might on occasion transmit a HELLO message in both directions (hence enabling the link for routing), while not being able to sustain continuous traffic. This would result in “route-flapping” and temporary loss of connectivity. With the experimental results as basis, we have been deploying simulations to reveal the impact of the various algorithmic improvements, described above.
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paper_title: A scalable location service for geographic ad hoc routing

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GLS is a new distributed location service which tracks mobile node locations. GLS combined with geographic forwarding allows the construction of ad hoc mobile networks that scale to a larger number of nodes than possible with previous work. GLS is decentralized and runs on the mobile nodes themselves, requiring no fixed infrastructure. Each mobile node periodically updates a small set of other nodes (its location servers) with its current location. A node sends its position updates to its location servers without knowing their actual identities, assisted by a predefined ordering of node identifiers and a predefined geographic hierarchy. Queries for a mobile node's location also use the predefined identifier ordering and spatial hierarchy to find a location server for that node. Experiments using the ns simulator for up to 600 mobile nodes show that the storage and bandwidth requirements of GLS grow slowly with the size of the network. Furthermore, GLS tolerates node failures well: each failure has only a limited effect and query performance degrades gracefully as nodes fail and restart. The query performance of GLS is also relatively insensitive to node speeds. Simple geographic forwarding combined with GLS compares favorably with Dynamic Source Routing (DSR): in larger networks (over 200 nodes) our approach delivers more packets, but consumes fewer network resources.
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paper_title: Location Systems for Ubiquitous Computing

paper_content:

This survey and taxonomy of location systems for mobile-computing applications describes a spectrum of current products and explores the latest in the field. To make sense of this domain, we have developed a taxonomy to help developers of location-aware applications better evaluate their options when choosing a location-sensing system. The taxonomy may also aid researchers in identifying opportunities for new location-sensing techniques.
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paper_title: Analyzing the Energy Consumption of IEEE 802.11 Ad Hoc Networks

paper_content:

This paper analyzes the energy consumption of ad hoc nodes using IEEE 802.11 interfaces. Our objective is to provide theoretical limits on the lifetime gains that can be achieved by different power saving techniques proposed in the literature. The evaluation takes into account the properties of the medium access protocol and the process of forwarding packets in ad hoc mode. The key point is to determine the node lifetime based on its average power consumption. The average power consumption is estimated considering how long the node remains sleeping, idle, receiving, or transmitting.
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paper_title: Geographic messaging in wireless ad hoc networks

paper_content:

This paper presents a network layer mechanism for the efficient dissemination of Global Positioning System (GPS) based node position in ad hoc networks, and shows its application to problems involving geographic awareness. In particular, we describe how, based on a "position database" maintained through the dissemination mechanism, a node of the network can direct messages to all the nodes currently present in a precise geographic area. The effectiveness and accuracy of the dissemination mechanism is demonstrated through the use of simulations. We show that for ad hoc networks with up to 60 nodes, the position database correctly determines which nodes are actually in the expected geographic area the 97% of the time.
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paper_title: Improving End-to-End Performance of TCP over Mobile Internetworks

paper_content:

Reliable transport protocols such as TCP use end-to-end flow, congestion and error control mechanisms to provide reliable delivery over an internetwork. However, the end-to-end performance of a TCP connection can suffer significant degradation in the presence of a wireless link. We are exploring alternatives for optimizing end-to-end performance of TCP connections across an internetwork consisting of both fixed and mobile networks. The central idea in our approach is to transparently split an end-to-end connection into two separate connections; one over the wireless link and other over the wired path. The connection over the wireless link may either use regular TCP or a specialized transport protocol optimized for better performance over a wireless link. Our approach does not require any changes to the existing protocol software on stationary hosts. Results of a systematic performance evaluation using both our approach and regular TCP show that our approach yields significant performance improvements.
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paper_title: A comparison of mechanisms for improving mobile IP handoff latency for end-to-end TCP

paper_content:

Handoff latency results in packet losses and severe End-to-End TCP performance degradation as TCP, perceiving these losses as congestion, causes source throttling or retransmission. In order to mitigate these effects, various Mobile IP(v6) extensions have been designed to augment the base Mobile IP with hierarchical registration management, address pre-fetching and local retransmission mechanisms. While these methods have reduced the impact of losses on TCP goodput and improved handoff latency, no comparative studies have been done regarding the relative performance amongst them. In this paper, we comprehensively evaluated the impact of layer-3 handoff latency on End-to-End TCP for various Mobile IP(v6) extensions. Five such frameworks are compared with the base Mobile IPv6 framework, namely, i) Hierarchical Mobile IPv6, ii) Hierarchical Mobile IPv6 with Fast-handover, iii) (Flat) Mobile IPv6 with Fast-handover, iv) Simultaneous Bindings, and v) Seamless handoff architecture for Mobile IP (S-MIP). We propose an evaluation model examining the effect of linear and ping-pong movement on handoff latency and TCP goodput, for all above frameworks. Our results show that S-MIP performs best under both ping-pong and linear movements during a handoff, with latency comparable to a layer-2 (access layer) handoff. All other frameworks suffer from packet losses and performance degradation of some sort. We also proposed an optimization for S-MIP which improves the performance by further eliminating the possibility of packets out of order, caused by the local packet forwarding mechanisms of S-MIP.
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paper_title: Impact of routing and link layers on TCP performance in mobile ad hoc networks

paper_content:

Mobile ad hoc networks have attracted attention lately as a means of providing continuous network connectivity to mobile computing devices, regardless of physical location. To date, a large amount of research has focused on the routing protocols needed in such an environment. In this paper, we investigate the effects that the routing and link layers have on TCP performance. In particular, we show how the route cache management strategy in an on-demand ad hoc routing protocol can significantly affect TCP performance. We also take a brief look at the impact of link layer retransmissions on TCP throughput in a fixed, wireless multihop network.
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paper_title: Improving TCP performance over mobile ad-hoc networks with out-of-order detection and response

paper_content:

In a Mobile Ad Hoc Network (MANET), temporary link failures and route changes happen frequently. With the assumption that all packet losses are due to congestion, TCP performs poorly in such environment. While there has been some research on improving TCP performance over MANET, most of them require feedback from the network or the lower layer. In this research, we explore a new approach to improve TCP performance by detecting and responding to out-of-order packet delivery events, which are the results of frequent route changes. In our simulation study, this approach had achieved on average 50% performance improvement, without requiring feedback from the network or the lower layer.
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paper_title: A comparison of TCP performance over three routing protocols for mobile ad hoc networks

paper_content:

We examine the performance of the TCP protocol for bulk-data transfers in mobile ad hoc networks (MANETs). We vary the number of TCP connections and compare the performances of three recently proposed on-demand (AODV and DSR) and adaptive proactive (ADV) routing algorithms. It has been shown in the literature that the congestion control mechanism of TCP reacts adversely to packet losses due to temporarily broken routes in wireless networks. So, we prospose a simple heuristic, called fixed RTO, to distinguish between route loss and network congestion and thereby improve the performance of the routing algorithms. Using the ns-2 simulator, we evaluate the performances of the three routing algorithms with the standard TCP Reno protocol and Reno with fixed RTO. Our results indicate that the proactive ADV algorithm performs well under a variety of conditions and that the fixed RTO technique improves the performances of the two on-demand algorithms significantly
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paper_title: Implementation and performance evaluation of Indirect TCP

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With the advent of small portable computers and the technological advances in wireless communications, mobile wireless computing is likely to become very popular in the near future. Wireless links are slower and less reliable compared to wired links and are prone to loss of signal due to noise and fading. Furthermore, host mobility can give rise to periods of disconnection from the fixed network. The use of existing network protocols, which were developed mainly for the high bandwidth and faster wired links, with mobile computers thus gives rise to unique performance problems arising from host mobility and due to the characteristics of wireless medium. Indirect protocols can isolate mobility and wireless related problems using mobility support routers (MSRs) as intermediaries, which also provide backward compatibility with fixed network protocols. We present the implementation and performance evaluation of I-TCP, which is an indirect transport layer protocol for mobile wireless environments. Throughput comparison with regular (BSD) TCP shows that I-TCP performs significantly better in a wide range of conditions related to wireless losses and host mobility. We also describe the implementation and performance of I-TCP handoffs.
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paper_title: A comparison of mechanisms for improving TCP performance over wireless links

paper_content:

Reliable transport protocols such as TCP are tuned to perform well in traditional networks where packet losses occur mostly because of congestion. However, networks with wireless and other lossy links also suffer from significant losses due to bit errors and handoffs. TCP responds to all losses by invoking congestion control and avoidance algorithms, resulting in degraded end-to end performance in wireless and lossy systems. We compare several schemes designed to improve the performance of TCP in such networks. We classify these schemes into three broad categories: end-to-end protocols, where loss recovery is performed by the sender; link-layer protocols that provide local reliability; and split-connection protocols that break the end-to-end connection into two parts at the base station. We present the results of several experiments performed in both LAN and WAN environments, using throughput and goodput as the metrics for comparison. Our results show that a reliable link-layer protocol that is TCP-aware provides very good performance. Furthermore, it is possible to achieve good performance without splitting the end-to-end connection at the base station. We also demonstrate that selective acknowledgments and explicit loss notifications result in significant performance improvements.
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paper_title: M-TCP: TCP for mobile cellular networks

paper_content:

Transport connections set up over wireless links are frequently plagued by problems such as - high bit error rate (BER), frequent disconnections of the mobile user, and low wireless bandwidth that may change dynamically. In this paper, we study the effects of frequent disconnections and low variable bandwidth on TCP throughput and propose a protocol that addresses this problem. We discuss the implementation (in NetBSD) of our protocol called M-TCP and compare its performance against other mobile TCP implementations. We show that M-TCP has two significant advantages over other solutions: (1) it maintains end-to-end TCP semantics and, (2) it delivers excellent performance for environments where the mobile encounters periods of disconnection.
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paper_title: A MAC protocol for full exploitation of directional antennas in ad-hoc wireless networks

paper_content:

Directional antennas in ad hoc networks offer many benefits compared with classical omnidirectional antennas. The most important include significant increase of spatial reuse, coverage range and subsequently network capacity as a whole. On the other hand, the use of directional antennas requires new approach in the design of a MAC protocol to fully exploit these benefits. Unfortunately, directional transmissions increase the hidden terminal problem, the problem of deafness and the problem of determination of neighbors' location. In this paper we propose a new MAC protocol that deals effectively with these problems while it exploits in an efficient way the advantages of the directional antennas. We evaluate our work through simulation study. Numerical results show that our protocol offers significant improvement compared to the performance of omni transmissions.
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paper_title: Directional virtual carrier sensing for directional antennas in mobile ad hoc networks

paper_content:

This paper presents a new carrier sensing mechanism called DVCS (Directional Virtual Carrier Sensing) for wireless communication using directional antennas. DVCS does not require specific antenna configurations or external devices. Instead it only needs information on AOA (Angle of Arrival) and antenna gain for each signal from the underlying physical device, both of which are commonly used for the adaptation of antenna pattern. DVCS also supports interoperability of directional and omni-directional antennas. In this study, the performance of DVCS for mobile ad hoc networks is evaluated using simulation with a realistic directional antenna model and the full IP protocol stack. The experimental results showed that compared with omni-directional communication, DVCS improved network capacity by a factor of 3 to 4 for a 100 node ad hoc network.
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paper_title: On designing MAC protocols for wireless networks using directional antennas

paper_content:

We investigate the possibility of using directional antennas for medium access control in wireless ad hoc networks. Previous research in ad hoc networks typically assumes the use of omnidirectional antennas at all nodes. With omnidirectional antennas, while two nodes are communicating using a given channel, MAC protocols such as IEEE 802.11 require all other nodes in the vicinity to remain silent. With directional antennas, two pairs of nodes located in each other's vicinity may potentially communicate simultaneously, increasing spatial reuse of the wireless channel. Range extension due to higher gain of directional antennas can also be useful in discovering fewer hop routes. However, new problems arise when using directional beams that simple modifications to 802.11 may not be able to mitigate. This paper identifies these problems and evaluates the tradeoffs associated with them. We also design a directional MAC protocol (MMAC) that uses multihop RTSs to establish links between distant nodes and then transmits CTS, DATA, and ACK over a single hop. While MMAC does not address all the problems identified with directional communication, it is an attempt to exploit the primary benefits of beamforming in the presence of some of these problems. Results show that MMAC can perform better than IEEE 802.11, although we find that the performance is dependent on the topology and flow patterns in the system.
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paper_title: Impact of Directional Antennas on Ad Hoc Routing

paper_content:

Previous research on directional antennas has been confined mostly to medium access control. However, it is necessary to evaluate the impact of directional antennas on the performance of routing protocols as well. In this paper, we identify the issues and evaluate the performance of an omnidirectional routing protocol, DSR, when executed over directional antennas. Using insights gained from simulations, we propose routing strategies suitable for directional communication. Our analysis shows that by using directional antennas, ad hoc networks may achieve better performance. However, scenarios exist in which omnidirectional antennas may be suitable.
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paper_title: Medium access control protocols using directional antennas in ad hoc networks

paper_content:

Using directional antennas can be beneficial for wireless ad hoc networks consisting of a collection of wireless hosts. To best utilize directional antennas, a suitable medium access control (MAC) protocol must be designed. Current MAC protocols, such as the IEEE 802.11 standard, do not benefit when using directional antennas, because these protocols have been designed for omnidirectional antennas. In this paper, we attempt to design new MAC protocols suitable for ad hoc networks based on directional antennas.
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paper_title: A comparison study of omnidirectional and directional MAC protocols for ad hoc networks

paper_content:

Traditional MAC protocols used in ad hoc networks employ omnidirectional antennas. Directional antennas have emerged as an alternative due to their capability of spatial reuse, low probability of detection, robustness to jamming, and other beneficial features. We conducted a comparison study of existing directional and omnidirectional MAC protocols by contrasting their features and evaluating their performance under various network load and topology. Specifically we presented rationale for the better performance of some directional antenna based MAC protocols by using the metric of effective spatial reuse, which is also evidenced by the simulation study.
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paper_title: Ad hoc networking with directional antennas: a complete system solution

paper_content:

In this paper, we present UDAAN ("utilizing directional antennas for ad hoc networking"), which is an interacting suite of modular network- and MAC-layer mechanisms for adaptive control of steered or switched antenna systems in an ad hoc network. UDAAN consists of several new mechanisms - a directional power-controlled MAC, neighbor discovery with beamforming, link characterization with directional antennas, proactive routing and forwarding all working cohesively to provide the first complete systems solution. We describe the development of a real-life ad hoc network testbed using UDAAN with switched directional antennas, and we discuss the lessons learned during field trials. High fidelity simulation results, using the same networking code as in the prototype, are also presented. For the range of parameters studied, our results show that UDAAN can produce up to a factor-of-10 improvement in throughput over omni-directional communications.
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paper_title: Using Directional Antennas for Medium Access Control in Ad Hoc Networks

paper_content:

A composition for use in the treatment for developing seedless fleshy berry of grapes. By treating the flower bunches of a grape tree with a composition containing gibberellin and cyclic 3',5'-adenylic acid in the form of an aqueous solution, it became possible to make seedless fleshy berry from grape trees belonging to varieties other than Delaware, namely belonging to Campbell-Arley, Berry A, Niagara, Kyoho, etc., from which seedless fleshy berry cannot be made by the conventional treatment with gibberellin.
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paper_title: Routing improvement using directional antennas in mobile ad hoc networks

paper_content:

In this paper, we present the initial design and evaluation of two techniques for routing improvement using directional antennas in mobile ad hoc networks. First, we use directional antennas to bridge permanent network partitions by adaptively transmitting selected packets over a longer distance, still transmitting most packets a shorter distance. Second, in a network without permanent partitions, we use directional antennas to repair routes in use, when an intermediate node moves out of wireless transmission range along the route; by using the capability of a directional antenna to transmit packets over a longer distance, we bridge the route breakage caused by the intermediate node's movement, thus reducing packet delivery latency. Through simulations, we demonstrate the effectiveness of our design in the context of the dynamic source routing protocol (DSR).
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paper_title: Secure Routing for Mobile Ad hoc Networks

paper_content:

Buttyan L.et al.found out a security flaw in Aridane and proposed a secure routing protocol,EndairA, which can resist attacks of active-1-1 according to ref[9].But unfortunately we discover an as yet unknown active-0-1 attack,"man-in-the-middle attack",which EndairA can't resist.So we propose a new secure routing protocol,En- dairALoc.Analysis shows that EndairALoc can not only inherit security of EndairA,but also resist"man-in-the-mid- dle attack"and even wormhole attack.Furthermore EndairALoc uses pairwise secret keys instead of public keys Endai- rA used,so compared with EndairA,EndairALoc can save more energy in the process of routing establishment.
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paper_title: SEAD: secure efficient distance vector routing for mobile wireless ad hoc networks

paper_content:

An ad hoc network is a collection of wireless computers (nodes), communicating among themselves over possibly multihop paths, without the help of any infrastructure such as base stations or access points. Although many previous ad hoc network routing protocols have been based in part on distance vector approaches, they have generally assumed a trusted environment. We design and evaluate the Secure Efficient Ad hoc Distance vector routing protocol (SEAD), a secure ad hoc network routing protocol based on the design of the Destination-Sequenced Distance-Vector routing protocol (DSDV). In order to support use with nodes of limited CPU processing capability, and to guard against denial-of-service (DoS) attacks in which an attacker attempts to cause other nodes to consume excess network bandwidth or processing time, we use efficient one-way hash functions and do not use asymmetric cryptographic operations in the protocol. SEAD performs well over the range of scenarios we tested, and is robust against multiple uncoordinated attackers creating incorrect routing state in any other node, even in spite of any active attackers or compromised nodes in the network.
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paper_title: Secure routing in wireless sensor networks: attacks and countermeasures

paper_content:

We consider routing security in wireless sensor networks. Many sensor network routing protocols have been proposed, but none of them have been designed with security as a goal. We propose security goals for routing in sensor networks, show how attacks against ad-hoc and peer-to-peer networks can be adapted into powerful attacks against sensor networks, introduce two classes of novel attacks against sensor networks sinkholes and HELLO floods, and analyze the security of all the major sensor network routing protocols. We describe crippling attacks against all of them and suggest countermeasures and design considerations. This is the first such analysis of secure routing in sensor networks.
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paper_title: Denial of Service in Sensor Networks

paper_content:

Sensor networks hold the promise of facilitating large-scale, real-time data processing in complex environments, helping to protect and monitor military, environmental, safety-critical, or domestic infrastructures and resources, Denial-of-service attacks against such networks, however, may permit real world damage to public health and safety. Without proper security mechanisms, networks will be confined to limited, controlled environments, negating much of the promise they hold. The limited ability of individual sensor nodes to thwart failure or attack makes ensuring network availability more difficult. To identify denial-of-service vulnerabilities, the authors analyzed two effective sensor network protocols that did not initially consider security. These examples demonstrate that consideration of security at design time is the best way to ensure successful network deployment.
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paper_title: Securing ad hoc routing protocols

paper_content:

We consider the problem of incorporating security mechanisms into routing protocols for ad hoc networks. Canned security solutions like IPSec are not applicable. We look at AODV[21] in detail and develop a security mechanism to protect its routing information. We also briefly discuss whether our techniques would also be applicable to other similar routing protocols and about how a key management scheme could be used in conjunction with the solution that we provide.
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paper_title: A survey of secure wireless ad hoc routing

paper_content:

Ad hoc networks use mobile nodes to enable communication outside wireless transmission range. Attacks on ad hoc network routing protocols disrupt network performance and reliability. The article reviews attacks on ad hoc networks and discusses current approaches for establishing cryptographic keys in ad hoc networks. We describe the state of research in secure ad hoc routing protocols and its research challenges.
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paper_title: Ariadne: a secure on-demand routing protocol for ad hoc networks

paper_content:

An ad hoc network is a group of wireless mobile computers (or nodes), in which individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range. Prior research in ad hoc networking has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we present attacks against routing in ad hoc networks, and we present the design and performance evaluation of a new secure on-demand ad hoc network routing protocol, called Ariadne. Ariadne prevents attackers or compromised nodes from tampering with uncompromised routes consisting of uncompromised nodes, and also prevents a large number of types of Denial-of-Service attacks. In addition, Ariadne is efficient, using only highly efficient symmetric cryptographic primitives.
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paper_title: Techniques for intrusion-resistant ad hoc routing algorithms (TIARA)

paper_content:

Architecture Technology Corporation (ATC) has developed a new approach for building intrusion resistant ad hoc networks called TIARA (Techniques for Intrusion-Resistant Ad Hoc Routing Algorithms). The approach, developed with funding from DARPA's Fault Tolerant Networks program, relies on extending the capabilities of existing ad hoc routing algorithms to handle intruders without modifying these algorithms. TIARA implements new network layer survivability mechanisms for detecting and recovering from intruder induced malicious faults that work in concert with existing ad hoc routing algorithms and augment their capabilities. The TIARA implementation architecture is designed to allow these survivability mechanisms to be "plugged" into existing wireless routers with little effort.
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paper_title: Wireless ad hoc network on underserved communities: An efficient solution for interactive digital TV

paper_content:

The Brazilian government intends to use the Digital TV technology as a vehicle of digital inclusion on underserved communities. The wireless ad hoc network is a low-cost, scalable and easy solution to implement the return channel. This work analyzes the performance of an ad hoc return channel using the wireless IEEE 802.11 technology in different Brazilian geographical scenarios. The results show that a high connectivity is achieved when more than 20% of the nodes are turned on, regardless of the position of the gateway. The influence of the number of hops and the number of transmitting nodes is also analyzed. A minimum throughput of 2 Mbps can be reached for increasing number of hops in the forwarding chain for a one-node transmission. Besides, when the number of transmitting nodes increases, the aggregated throughput can achieve 3.5 Mbps. The results show that the ad hoc network is a promising solution for the return channel of the interactive Digital TV.
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Title: A Survey on Wireless Ad Hoc Networks
Section 1: Introduction
Description 1: This section introduces wireless ad hoc networks, explaining their characteristics, advantages, and typical use cases, and outlining the paper's structure.

Section 2: Medium Access Control Protocols
Description 2: This section discusses various MAC protocols designed for wireless ad hoc networks, including contention-free and contention-based schemes, and their strategies for efficient medium access.

Section 3: Multiple Channel Protocols
Description 3: This section explores MAC protocols employing multiple channels to improve overall network performance by reducing collisions and increasing available bandwidth.

Section 4: Power-aware Protocols
Description 4: This section focuses on protocols that implement energy-saving techniques for battery-powered mobile devices, such as active-standby switching, power setting, and retransmission avoidance.

Section 5: QoS-aware Protocols
Description 5: This section addresses protocols designed to provide Quality of Service (QoS) in ad hoc networks, ensuring limited end-to-end delay and minimum bandwidth for specific flows.

Section 6: Enabling Technologies
Description 6: This section gives an overview of Bluetooth and IEEE 802.11 technologies, which are the foundational standards for implementing wireless ad hoc networks, describing their MAC and physical layer characteristics.

Section 7: Routing Protocols
Description 7: This section examines the routing challenges in wireless ad hoc networks and compares different routing protocols, categorized into topology-based and position-based protocols.

Section 8: Transport Protocols
Description 8: This section delves into TCP performance issues in wireless ad hoc networks and explores various proposals for enhancing TCP efficiency, including split connection and cross-layer approaches.

Section 9: Directional Antennas
Description 9: This section investigates the use of directional antennas in ad hoc networks, discussing their advantages, the problems arising from their use, and proposed MAC and routing protocols to leverage their benefits.

Section 10: Security
Description 10: This section explores the security challenges in wireless ad hoc networks, identifying common attacks and discussing various protocols designed to secure ad hoc routing and communication.

Section 11: Underserved Communities
Description 11: This section describes the application of wireless ad hoc networks in fostering digital inclusion within underserved communities, emphasizing the deployment of community networks for social inclusion.