Recently there has been a great deal of research on using mobility in sensor networks to assist in the initial deployment of nodes. Mobile sensors are useful in this environment because they can move to locations that meet sensing coverage requirements. This paper explores the motion capability to relocate sensors to deal with sensor failure or respond to new events. We define the problem of sensor relocation and propose a two-phase sensor relocation solution: redundant sensors are first identified and then relocated to the target location. We propose a Grid-Quorum solution to quickly locate the closest redundant sensor with low message complexity, and propose to use cascaded movement to relocate the redundant sensor in a timely, efficient and balanced way. Simulation results verify that the proposed solution outperforms others in terms of relocation time, total energy consumption, and minimum remaining energy.

http://www.cse.psu.edu/~tfl12/paper/infocom05_sensor.pdf

Sensor relocation in mobile sensor networks

Review: Coverage and connectivity issues in wireless sensor networks: A survey

An attack graph is a succinct representation of all paths through a system that end in a state where an intruder has successfully achieved his goal. Today Red Teams determine the vulnerability of networked systems by drawing gigantic attack graphs by hand. Constructing attack graphs by hand is tedious, error-prone, and impractical for large systems. By viewing an attack as a violation of a safety property, we can use off-the-shelf model checking technology to produce attack graphs automatically: a successful path from the intruder's viewpoint is a counterexample produced by the model checker In this paper we present an algorithm for generating attack graphs using model checking as a subroutine. Security analysts use attack graphs for detection, defense and forensics. In this paper we present a minimization analysis technique that allows analysts to decide which minimal set of security measures would guarantee the safety of the system. We provide a formal characterization of this problem: we prove that it is polynomially equivalent to the minimum hitting set problem and we present a greedy algorithm with provable bounds. We also present a reliability analysis technique that allows analysts to perform a simple cost-benefit trade-off depending on the likelihoods of attacks. By interpreting attack graphs as Markov Decision Processes we can use the value iteration algorithm to compute the probabilities of intruder success for each attack the graph.

Two Formal Analyses of Attack Graphs

Several anomalies can occur in wireless sensor networks that impair their desired functionalities i.e., sensing and communication. Different kinds of holes can form in such networks creating geographically correlated problem areas such as coverage holes, routing holes, jamming holes, sink/black holes and worm holes, etc. We detail in this paper different types of holes, discuss their characteristics and study their effects on successful working of a sensor network. We present state-of-the-art in research for addressing the holes related problems in wireless sensor networks and discuss the relative strengths and short-comings of the proposed solutions for combating different kinds of holes. We conclude by highlighting future research directions.

https://cs.wmich.edu/gupta/teaching/cs5950/fall2011/holesProblem%20in%20WSNs%20-%20a%20survey%20p4-ahmed%20ACM%20sigmobile%20reviews%20april2005.pdf

The holes problem in wireless sensor networks: a survey

This paper demonstrates the advantages of using controlled mobility in wireless sensor networks (WSNs) for increasing their lifetime, i.e., the period of time the network is able to provide its intended functionalities. More specifically, for WSNs that comprise a large number of statically placed sensor nodes transmitting data to a collection point (the sink), we show that by controlling the sink movements we can obtain remarkable lifetime improvements. In order to determine sink movements, we first define a Mixed Integer Linear Programming (MILP) analytical model whose solution determines those sink routes that maximize network lifetime. Our contribution expands further by defining the first heuristics for controlled sink movements that are fully distributed and localized. Our Greedy Maximum Residual Energy (GMRE) heuristic moves the sink from its current location to a new site as if drawn toward the area where nodes have the highest residual energy. We also introduce a simple distributed mobility scheme (Random Movement or RM) according to which the sink moves uncontrolled and randomly throughout the network. The different mobility schemes are compared through extensive ns2-based simulations in networks with different nodes deployment, data routing protocols, and constraints on the sink movements. In all considered scenarios, we observe that moving the sink always increases network lifetime. In particular, our experiments show that controlling the mobility of the sink leads to remarkable improvements, which are as high as sixfold compared to having the sink statically (and optimally) placed, and as high as twofold compared to uncontrolled mobility.

http://senseslab.di.uniroma1.it/administrator/components/com_jresearch/files/publications/Controlled_Sink_Mobility_for_P.pdf

Controlled sink mobility for prolonging wireless sensor networks lifetime

In some harsh environments, manually deploying sensors is impossible. Alternative methods may lead to imprecise placement resulting in coverage holes. To provide the required high coverage in these situations, we propose to deploy sensor networks composed of a mixture of mobile and static sensors in which mobile sensors can move from dense areas to sparse areas to improve the overall coverage. This paper presents a bidding protocol to assist the movement of mobile sensors. In the protocol, static sensors detect coverage holes locally by using Voronoi diagrams, and bid for mobile sensors based on the size of the detected hole. Mobile sensors choose coverage holes to heal based on the bid. Simulation results show that our algorithm provides suitable tradeoff between coverage and sensor cost.

http://www.cse.psu.edu/~tfl12/paper/icnp03.pdf

A bidding protocol for deploying mobile sensors

Early first and second generation (1G and 2G, respectively) wireless telecommunication networks were isolated in the sense that their signaling and control infrastructure was not directly accessible to end subscribers. The vision of the next generation 3G wireless telecommunication network is to use IP technologies for control and transport. The introduction of IP technologies has opened up a new generation of IP-based services that must interwork with traditional 3G wireless telecommunication networks. Cross Network Services will use a combination of Internet-based data and data from the wireless telecommunication network to provide services to the wireless subscriber. They will be multi-vendor, multi-domain, and will cater to a wide variety of needs. An example of such a Cross Network Service is the Email Based Call Forwarding Service (CFS), where the status of the subscriber's email inbox is used to trigger call forwarding in the wireless telecommunication network.

http://www.cse.psu.edu/~tfl12/paper/ISI_final.pdf

A taxonomy of cyber attacks on 3g networks

Source locations of events are sensitive contextual information that needs to be protected in sensor networks. Previous work focuses on either an active local attacker that traces back to a real source in a hop-by-hop fashion, or a passive global attacker that eavesdrops/analyzes all network traffic to discover real sources. An active global attack model, which is more realistic and powerful than current ones, has not been studied yet. In this paper, we not only formalize this strong attack model, but also propose countermeasures against it.

/pdf/an-active-global-attack-model-for-sensor-source-location-mdvdfkopjd.pdf

An Active Global Attack Model for Sensor Source Location Privacy: Analysis and Countermeasures

This paper presents the Cellular Network Vulnerability Assessment Toolkit - CAT, designed for end-to-end vulnerability assessment of 3G networks. It is the first tool of its kind to model and represent 3G network vulnerabilities and attacks as attack graphs. CAT uses freely available 3G telecommunication specifications written in SDL, the standard Specification and Description Language to produce attack graphs. Attack graphs generated by CAT are unique due to their: (1) global representation of the network, (2) independence from physical deployments, and (3) depiction of the 3G attack graph model and cascading effects.

/pdf/cat-a-practical-graph-sdl-based-toolkit-for-vulnerability-2k6facn07f.pdf

CAT — A Practical Graph & SDL Based Toolkit for Vulnerability Assessment of 3G Networks

A major security vulnerability in the mobile telecommunication network is that wireline signaling messages are cleartext. The latest protocol for wireline signaling message security is mobile application part security (MAPSec), which protects MAP (a signaling message protocol) messages on the link between nodes. MAPSec is a limited solution because it still leaves MAP signaling messages unsecured in intermediate nodes, and also leaves other wireline signaling message protocols unsecured both on the link and in intermediate nodes. Hence, there is a need for a more comprehensive wireline security scheme to protect all types of wireline signaling messages end-to-end i.e., both on the link and in intermediate nodes. As a solution, we propose EndSec, an end-to-end wireline signaling message security protocol for all types of signaling messages. EndSec works by inserting cryptographic checks on data items in signaling messages, has capabilities to self-detect and repair corruption, and identifies the nodes causing corruption.

Thomas F. LaPorta

Papers

A bidding protocol for deploying mobile sensors

A taxonomy of cyber attacks on 3g networks

An Active Global Attack Model for Sensor Source Location Privacy: Analysis and Countermeasures

CAT — A Practical Graph & SDL Based Toolkit for Vulnerability Assessment of 3G Networks

EndSec: An end-to-end message security protocol for mobile telecommunication networks