http://www.csun.edu/~andrzej/COMP529-S05/papers/Mesh%20Networks%20Survey.pdf

Wireless mesh networks: a survey

In this paper, we tackle one fundamental problem in Underwater Sensor Networks (UWSNs): robust, scalable and energy efficient routing. UWSNs are significantly different from terrestrial sensor networks in the following aspects: low bandwidth, high latency, node float mobility (resulting in high network dynamics), high error probability, and 3-dimensional space. These new features bring many challenges to the network protocol design of UWSNs. In this paper, we propose a novel routing protocol, called vector-based forwarding (VBF), to provide robust, scalable and energy efficient routing. VBF is essentially a position-based routing approach: nodes close to the “vector” from the source to the destination will forward the message. In this way, only a small fraction of the nodes are involved in routing. VBF also adopts a localized and distributed self-adaptation algorithm which allows nodes to weigh the benefit of forwarding packets and thus reduce energy consumption by discarding the low benefit packets. Through simulation experiments, we show the promising performance of VBF.

/pdf/vbf-vector-based-forwarding-protocol-for-underwater-sensor-4xrrdftwh0.pdf

VBF: vector-based forwarding protocol for underwater sensor networks

Energy is of primary importance in wireless sensor networks. By being able to estimate the energy consumption of the sensor nodes, applications and routing protocols are able to make informed decisions that increase the lifetime of the sensor network. However, it is in general not possible to measure the energy consumption on popular sensor node platforms. In this paper, we present and evaluate a software-based on-line energy estimation mechanism that estimates the energy consumption of a sensor node. We evaluate the mechanism by comparing the estimated energy consumption with the lifetime of capacitor-powered sensor nodes. By implementing and evaluating the X-MAC protocol, we show how software-based on-line energy estimation can be used to empirically evaluate the energy efficiency of sensor network protocols.

/pdf/software-based-on-line-energy-estimation-for-sensor-nodes-2fczdw9wwa.pdf

Software-based on-line energy estimation for sensor nodes

Intervehicle communication (IVC) is an emerging topic in research and application that is getting increasing attention from all major car manufacturers. In this paper, a novel method for scalable information dissemination in highly mobile ad hoc networks is proposed: segment-oriented data abstraction and dissemination (SODAD). With SODAD, information can be distributed in an information range multiple orders of magnitude larger than the transmission range of the air interface, even if only 1%-3% of all vehicles are equipped with an IVC system, e.g., during market introduction. By restricting the method to the dissemination of map/position-based data, scalability is achieved. In the second half of this paper, an example application for the SODAD method is presented: a self-organizing traffic-information system (SOTIS). In SOTIS, a car is equipped with a satellite navigation receiver, an IVC system, and a digital map. Each individual vehicle collects traffic information for its local area. Using the digital map, the traffic information is analyzed based on road segments. By distributing the information in the ad hoc intervehicle network using the SODAD method, a decentralized traffic information system is created. The performance of the proposed methods is evaluated using network simulation with vehicular mobility models. Simulation results for typical scenarios are presented. Furthermore, a prototype implementation based on commercially available standard hardware demonstrates the feasibility of the proposed approach.

Information dissemination in self-organizing intervehicle networks

Survey A survey of routing protocols for smart grid communications

BLR: beacon-less routing algorithm for mobile ad hoc networks

In this paper we present a simple and stateless broadcasting protocol called Dynamic Delayed Broadcasting (DDB) which allows locally optimal broadcasting without any prior knowledge of the neighborhood. As DDB does not require any transmissions of control messages, it conserves critical network resources such as battery power and bandwidth. Local optimality is achieved by applying a principle of Dynamic Forwarding Delay (DFD) which delays the transmissions dynamically and in a completely distributed way at the receiving nodes ensuring nodes with a higher probability to reach new nodes transmit first. An optimized performance of DDB over other stateless protocols is shown by analytical results. Furthermore, simulation results show that, unlike stateful broadcasting protocols, the performance of DDB does not suffer in dynamic topologies caused by mobility and sleep cycles of nodes. These results together with its simplicity and the conservation of network resources, as no control message transmissions are required, make DDB especially suited for sensor and vehicular ad-hoc networks.

/pdf/optimized-stateless-broadcasting-in-wireless-multi-hop-by1mftjism.pdf

Optimized Stateless Broadcasting in Wireless Multi-Hop Networks

In position-based routing protocols, each node periodically transmits a short hello message (called beacon) to announce its presence and position. Receiving nodes list all known neighbor nodes with their position in the neighbor table and remove entries after they have failed to receive a beacon for a certain time from the corresponding node. In highly dynamic networks, the information stored in the neighbor table is often outdated and does no longer reflect the actual topology of the network causing retransmissions and rerouting that consume bandwidth and increase latency. An analysis on the possible impact of beacons due outdated and inaccurate neighbor tables is needed. We quantify by analytical and simulation means the possible performance loss and explore the limitations of position-based routing protocols which use beaconing. In highly mobile ad-hoc networks, the delay can increase by a factor of 20. The neighbor table inaccuracy is the main source of packet loss in uncongested networks. We propose and evaluate several concrete mechanisms to improve the accuracy of neighborhood information, e.g., by dynamic adaptation of the timer values when beacons are broadcasted, and show their effectiveness by extensive simulation.

Evaluating the limitations of and alternatives in beaconing

In this paper we present our experimental lifetime measurements for two implementations of MAC protocols designed for wireless sensor networks. We have implemented the TDMA based LMAC and the contention-based TEEM on the ESB nodes developed at FU Berlin. We show the energy requirements of these protocols on the respective hardware and also present figures for the trade off between robustness and energy consumption of these protocols. The main contribution of this paper consists in real world measurements giving an idea of energy conserving MAC protocols’ potential to extend node lifetime.

Experimental Lifetime Evaluation for MAC Protocols on Real Sensor Hardware

Authentication and Authorization Infrastructures (AAIs) are single sign-on systems. Their purpose is authenticating a user once, i.e. locally at the user’s so-called home organization, and then checking authorization of requested resource accesses based on user attributes the user’s home organization delivers. AAIs are just about being widely employed, and Switzerland is playing a pioneering role in AAI deployment as the national research and education network provider SWITCH has managed to get all Swiss universities involved in setting up an AAI. In that context, the SWITCH AAI is used, for instance, to control access to e-learning resources. We will report in this paper on SWITCH AAI and its use in the VITELS (Virtual Internet and Telecommunications Laboratory for Switzerland). By doing so, we will discuss how the AAI middleware Shibboleth is used to implement a concrete AAI. After explaining how Shibboleth is used to implement SWITCH AAI, we will discuss how VITELS integrates into SWITCH AAI, including server (or better: service) integration of VITELS into SWITCH AAI as well as discussing which attributes are delivered cross organizations.

/pdf/case-study-of-the-usage-of-an-authentication-and-2s5elb6wt7.pdf

Thomas Bernoulli

Papers

BLR: beacon-less routing algorithm for mobile ad hoc networks

Optimized Stateless Broadcasting in Wireless Multi-Hop Networks

Evaluating the limitations of and alternatives in beaconing

Experimental Lifetime Evaluation for MAC Protocols on Real Sensor Hardware

Case Study of the Usage of an Authentication and Authorization Infrastructure (AAI) in an E-learning Project