In this paper, we exploit the capture-effect for channel allocation. We experimentally show the characteristics of capture-effect across different channels, over time, and in different network densities. Then, we introduce CACA, an effective channel assignment protocol for wireless sensor networks. Traditional channel assignment protocols utilize all available channels to minimize interferences between any adjacent links. However, their performances are often not much better than the case of using single channel only. This is mainly due to an assumption that all channels are independent and quality of all channels are similar. However, this is a false assumption. In fact, there are only a few channels that show very good quality at any given time. The CACA avoids this problem by utilizing a few good channels and reuse these channels. When the channels are reused it relies on the capture-effect to ensure at least one of the contending nodes to transmit successfully. Maximizing this capture probability is a main objective of the CACA whenever the channels need to be reused. We evaluate the CACA on a 140-node wireless sensor network testbed and compare its performance with another benchmark protocol. Our results indicate that the CACA can improve the packet reception ratio of every link. As a result of this improvement, end-to-end throughput increases upto 100% in the case of a wireless sensor network with bursty traffic.

Wireless Body area networks comprise of sensor nodes attached on or implanted inside the human body and promise large improvements in patients health monitoring. However, the heat generated by the sensor nodes circuitry can cause damage to the tissues in the human body. Therefore, in an attempt to reduce the heat generated, efficient sleep cycles and temperature-aware routing for the sensor nodes should be established. In this paper, we present a probabilistic sleep cycle management and a temperature aware data-packet routing algorithm.

The number of hops from Mesh Routers (MRs) to an Internet gateway (IGW) plays an important role in determining the performance of a wireless mesh network (WMN). A recent patent has introduced a mechanism of using an existing femtocell (FC) as an additional potential IGW so that the performance of a WMN could be enhanced. Such an integration of WMN with FCs enables an increase in WMN's overall capacity. But, due to FCs' unpredictable operating times and uninformed disconnections, MRs require reliable and efficient schedule for switching between available FCs which has not been analyzed in the patent. The switching can be done in a push based preemptive or a pull based non-preemptive manner. In this paper, we formulate both these switching schemes for a WMN-FC integrated network as approximate statistical models based on a Markovian process. We also determine a switching schedule of FCs for each of MR based on reliable uncapacitated facility location (RUFL) problem. We extend an existing RUFL problem to incorporate dynamic operating nature of multiple FCs which display dynamic available/unavailable patterns for additional potential IGWs. Extensive simulations are carried out to validate our proposed statistical models and establish the performance of these switching schemes.

There are many ways to determine the boundary of an event based on Satellite imaging which does not provide accurate information. In many situations, there may not be enough time to monitor the effect of emergency and the affected area. Moreover, the event region could continuously change in the geographical region and a robust deployment of sensors is desirable that could capture maximum information about the entire event as soon as possible and continue capturing information without a break. These events are not physically accessible and most of the sensor deployments are static to check if they can fully cover an event. We explore these issues in this work and look at dynamic sensor network deployment strategies.

Modern multi-hop wireless networks employ a number of sophisticated schemes to secure the network against hostile attacks. However, constant improvements in any security mechanism is matched by ever increasing sophisticated attacks. Therefore, there is a constant need to develop innovative schemes, especially for applications where the integrity of the message is vital. Attacks from trusted byzantine nodes that belong to the network itself are particularly challenging, as these nodes have a hidden malicious component and have complete access to the network resources. Previous works have studied these attacks and countermeasures for multi-hop networks and on networks capable of performing Network Coding. In this paper, we identify an inherent security benefit of Analog Network Coding and show how it can be used to design a novel Dual Non-adjacent Watchdog scheme that can detect a set of malicious byzantine attacks.

Abstract In a static wireless sensor network (WSN), sensors close to the base station (BS) run out of energy at a much faster rate than sensors in other parts of the network. This is because the sensor close to the BS always relays the data for other sensors, resulting in an unequal distribution of network residual energy. In this paper, we propose a scheme for enhancing the network lifetime using multiple mobile cluster heads (CHs) that can move in the WSN in a controllable manner. The CH controllably moves toward the energy‐rich sensors or the event area, offering the benefits of maintaining the remaining energy more evenly, or eliminating multihop transmission. Therefore, the proposed scheme increases the network lifetime. We theoretically analyze the energy consumption in our scheme and propose three heuristical mobility strategies. We further study the collaboration among CHs in order to maintain their connectivity to the BS to ensure the delay requirement for real‐time applications. Simulation shows that network lifetime is increased by upto 75% over existing approach by making CHs always move toward a stable equilibrium point. Our connectivity algorithm provides a best case improvement of 40% in transmission delays over existing schemes. Copyright © 2009 John Wiley & Sons, Ltd.

We present a mechanism for optimum distribution of internet traffic over heterogeneous network environment. A heterogeneous network can be considered as a combination of multiple homogenous networks available simultaneously to the end users. For simplicity, each network has been modeled as a M/M/1 queue. We aim to minimize the number of jobs in each queue subject to constraints. The optimization problem has been achieved through the use of Lagrange multiplier. Depending on their service rate the formulation done in this work is shown to optimally divide the rate of incoming traffic into different networks.

In this demo, a new application for the Wireless Sensor Networks (WSN) is presented. This is the first time WSN is used to in the music field, where the music is being manipulated and changed according to the movement of the dancer. Twenty-three tmote sensors have been deployed on a dancing stage, and two sensors were attached to the arms of each dancer. Information collected from sensors deployed on the stage are being sent and processed at a central location where the music being played is manipulated. This project is the first phase of collaboration in a multi-disciplinary research between the Computer Science department and the College-Conservatory of Music at the University of Cincinnati.

This paper proposes a scheme for enhancement of network Lifetime using MObile Clusterheads (LIMOC) in a wireless sensor network (WSN). The low energy, static sensor nodes sense physical parameters and route the data to the highly energy-rich nodes called ClusterHeads (CHs) which are mobile and can transmit data directly to the base station (BS). A collaborative strategy among the CHs increases the lifetime (hence residual energy) of the network further. Simulation has shown that residual energy of the network can be improved by 45% by making the CHs always move towards the event in an event-driven network. For general cases, increased energy savings is obtained by making the CH move towards the center of equilibrium w.r.t. to both the total residual energy and data flow of the network.