Garth V. Crosby

Cluster-Based Reputation and Trust for Wireless Sensor Networks

Using a reputation-based trust framework for wireless sensor networks we introduce a mechanism that prevents the election of compromised or malicious nodes as cluster heads, through trust based decision making. We employ a secure cluster formation algorithm to facilitate the establishment of trusted clusters via pre-distributed keys. Reputation and trust is built over time and allow the continuation of trusted cluster heads elections. We performed an evaluation of our approach through simulations. The results indicate clear advantages of our approach in protecting the information of our network by preventing the election of untrustworthy cluster heads.

Evolution of Cooperation in Multi-Class Wireless Sensor Networks

The real-world implementation of a just theoretically elaborated idea is sometimes cumbersome, often a couple of obstacles have to be overcome. Thats likewise in the area of wireless sensor networks (WSN), but complicated by some further restrictions, e.g. little memory or low power consumption. One well-known and often required application within WSN is the geographical localization of several sensor nodes. Thats why this paper deals with some problems arising during the development of a WSN using the time difference of arrival (TDoA) of ultrasound and radio signals for positioning. Its focus is on handling of microcontroller difficulties like little memory, low computational power or low energy consumption as well as hardware driven failures like inaccurate measurements or node failures.Cooperation among nodes is essential for the reliable routing of packets in large scale wireless sensor networks from nodes to base station. Most of the previous works have assumed a single governing authority with full cooperation among nodes. The assumption of node cooperation, however, cannot be applied to wireless sensor networks (WSNs) with more than one governing authority. In this paper, we introduce the concept of multi-class wireless sensor networks where each class is governed by a different authority. We study the evolution of cooperation in static and mobile multi-class wireless sensor networks using evolutionary game theory which has, to the best of our knowledge, never been attempted before. We then propose a novel localized distributive algorithm we call the patient grim strategy (PGS), and demonstrate that it provides a Nash equilibrium solution to the game theoretic problem of cooperation in multi-class static wireless sensor networks. Our simulation results show that in static multi-class WSNs populations playing the prisoners dilemma, significant propensities to cooperate can evolve.

Location-aware, Trust-based Detection and Isolation of Compromised Nodes in Wireless Sensor Networks

The detection and isolation of compromised nodes in wireless sensor networks is a difficult task. However, failure to identify and isolate compromised nodes results in significant security breaches which lowers the integrity of gathered data. Using a reputation-based trust framework for wireless sensor networks we introduce a location-aware, trust-based protocol that detects and isolates compromised nodes. We employ a secure cluster formation algorithm to facilitate the establishment of trusted clusters via pre-distributed keys. Reputation and trust is built over time through the monitoring of neighboring nodes. Our scheme provides a mechanism for developing reputation and trust so that a device can determine whether other devices have been compromised, and take corrective action, through negative information sharing and independent trust-based decision making. We also present a simple location verification algorithm that utilizes the received signal strength information in the process of verifying reported location information. The effectiveness of our approach in the detection and isolation of compromise nodes is validated through simulation. The results indicate that our scheme provides an effective mechanism for detecting and isolating compromised colluding nodes.

Advances and challenges of wireless body area networks for healthcare applications

The term wireless body area network (WBAN) is used to describe a network of devices connected wirelessly for communication on, in and near the body. In this paper, we survey the current state of various aspects of WBAN technologies that are being used in healthcare applications. In particular, we examine the following areas: monitoring and sensing, power efficient protocols, system architectures, routing, and security. We conclude by discussing open research issues, their potential solutions and future trends.

Wireless sensor networks and LTE-A network convergence

In recent years, machine-to-machine (M2M) networks, which do not require direct human intervention, is increasing at a rapid pace. Meanwhile, the need of a wireless platform with a vast coverage and low network deployment cost for controlling and monitoring these M2M networks has not yet been met. Mobile cellular networks (MCNs) and wireless sensor networks (WSNs) are emerging as two heterogeneous networks that can meet the challenges of M2M communication through network convergence. In this paper, we propose a model for network convergence between a Long Term Evolution-Advance (LTE-A) cellular network and a wireless sensor network. Quality of service (QoS) issues are assessed by a comparative study of the network delay in tight coupling and loose coupling LTE-A configurations. Simulation results indicate that the network delay in our proposed converged network is acceptable for various M2M applications.

New Security Approach for ZigBee Weaknesses

Abstract The latest version of ZigBee offers improvements over many aspects like low power consumption, flexibility and inexpensive deployment. However problems persist, as the enhanced protocol still has many security weaknesses due to the fact that constrained wireless sensor network devises cannot uses standard security protocols such as public key cryptography mechanisms. In this paper, we highlight relevant security concerns related to ZigBee security features, then we propose a new approach suitable for ZigBee enabled wireless sensor networks. The proposed solution decreases considerably the likelihood of successful attacks,and reduces security impact in the event of a node compromise. Lastly we discuss the security and performance related to the proposed scheme.

Using network traffic to infer power levels in wireless sensor nodes

In this paper we leverage the concept of information leakage to demonstrate the correlation between network traffic and available power levels in wireless sensor nodes brought about as a result of dynamic duty cycling. We show that this correlation can be used to remotely infer sensor node power levels. Essentially, our premise is that by determining the send rate of a wireless sensor node the current duty cycle mode and thus available power level of the node can be inferred. Our scheme, namely Power Efficient Path Selection (PEPS), is motivated by the fact that dynamic duty cycling attempts to streamline power usage in wireless sensor nodes by decreasing radio usage, which directly affects the nodes network traffic send rate. PEPS is an enhancement to the shortest path algorithm that allows us to 1) reduce the volume of periodic messages since the energy level of neighboring nodes and their statuses are inferred rather than communicated via control packets, and 2) extend the lifetime of a wireless sensor network (WSN) through the selection of energy-aware communication paths. We demonstrate the performance and feasibility of PEPS through simulation and comparative study with the traditional Shortest Path algorithm. The results indicate significant energy savings and the extension of the lifetime of the wireless sensor network when PEPS is employed.

On Optimal Slot Allocation for Reservation TDMA MAC Protocol in Shadow Fading Environment

This paper investigates the problem of providing delay guarantees to time-sensitive users sharing an uplink channel. The channel is a time slotted joint AWGN and impulsive noise channel in a shadow fading environment. Guaranteeing delay in shadow fading and noisy environment requires the MAC layer to be aware of the application delay requirements and the physical layer characteristics of the wireless channel. One of the important components of the base station MAC is the slot allocation module that allocates time slots to users. Existing slot allocation schemes use linear proportional schemes based on the queue state and priority factor. We develop an optimal slot allocation scheme that bases its allocation decision on the buffer content, the traffic class factor and the wireless channel quality. We specify the wireless channel quality in terms of the probability of connectivity between users and the base station and develop a method of estimating this quantity. Instead of absolute no transmission during bad wireless link states our optimal slot allocation module allots fewer slots in bad link states. The slot allocation module is used in a reservation TDMA base station (BS) MAC to control queuing delay and improve throughput. The performance of the slot allocation scheme is evaluated using OPNET simulation.

Wireless Body Area Networks in mHealth

Wireless body area networks (WBANs) are emerging as important networks, applicable in various fields. In this chapter a comprehensive survey of WBANs that are designed for applications in healthcare is presented. The survey consists of stand-alone sections focusing on important aspects of WBANs. Topics covered are: monitoring and sensing, power efficient protocols, physical layer, MAC protocols, routing, system architectures and security. The chapter concludes with a discussion of open research issues, their potential solutions and future trends.

Using network traffic to infer compromised neighbors in wireless sensor nodes

This work introduces a novel security framework for wireless sensor networks (WSN) based on dynamic duty cycle, which allows nodes to detect their compromised neighbors based on unanticipated fluctuations in network traffic send rate over time. Our framework was assessed by its ability to detect advanced WSN threats (e.g., active, passive, or both attacks). One of the benefits of this framework is that it reduces all threats to unanticipated power dissipation. In other words, the framework assumes any neighbor not conforming to predicted power levels has been communicating with an unauthorized node, and thus is compromised. This threat model is emulated by applying pseudo random but bound (large to small) power dissipations to arbitrary nodes. Simulation results demonstrated that this framework was effective in detecting and isolating compromised sensor nodes.