ad hoc networks

The Smart Stone Protocol (SSP) has been developed to achieve rapid synchronization in a wireless sensor network, establish Time Division Multiple Access (TDMA) communication slots, and perform distributed sensing with global shared awareness. The SSP achieves a synchronization precision of 50μs among receivers. The sender is synchronized to the receivers using a novel scheme to identify the closest comparable times on the sender and receiver. The protocol is tightly related to events that occur in the mote hardware, and is ...

Mobile Ad Hoc Network (MANET) is a collection of communication devices or nodes that wish to communicate without any fixed infrastructure and pre-determined organization of available links. The nodes in MANET themselves are responsible for dynamically discovering other nodes to communicate. Although the ongoing trend is to adopt ad hoc networks for commercial uses due to their certain unique properties, the main challenge is the vulnerability to security attacks. A number of challenges like open peer-to-peer network architecture, stringent resource ...

An important concept in network security is trust, interpreted as a relation among entities that participate in various protocols. Trust relations are based on evidence related to the previous interactions of entities within a protocol. In this work, we are focusing on the evaluation process of trust evidence in Ad Hoc Networks. Because of the dynamic nature of Ad Hoc Networks, trust evidence may be uncertain and incomplete. Also, no pre-established infrastructure can be assumed. The process is formulated as ...

In this dissertation ("Distributed Source Localization and Tracking Algorithms for Ad-hoc Acoustic Sensor Networks"), we construct an algorithmic framework for systematic tracking of moving sources in large-scale sensor networks. The tracking algorithms we developed generate the estimates of the tracking locations from fusion of space-time data by first fusing the data in space and subsequently by fusing the data in time. Fusion in space is performed by fusing current sensed data that is sufficiently high-quality from the sensor nodes to ...

Ad-hoc wireless networks distinguish themselves from their traditional wired counterparts by three unique characteristics: mobility, lack of infrastructure, and shared wireless channel. These properties have gained popularity in various military and civilian applications, but have also introduced challenging problems in terms of ensuring satisfying network performance and network security. Ad hoc networks are a fertile ground for new threats and security problems. We start by demonstrating how new covert attacks can be launched by using the ad hoc network protocols. ...

The ongoing efforts to apply advanced technologies to help solve transportation problems advanced the growing trend of integrating mobile wireless communications into transportation systems. In particular, vehicular ad hoc networks (VANETs) allow vehicles to constitute a decentralized traffic information system on roadways and to share their own information. This research focused on the development of an integrated transportation and communication simulation framework to build a more realistic environment with which to study VANETs, as compared to previous studies. This research ...

Connectivity is one of the most fundamental properties of wireless ad-hoc networks as most network functions are predicated upon the network being connected. Although increasing node transmission power will improve network connectivity, too large a power level is not feasible as energy is a scarce resource in wireless ad-hoc networks. Thus, it is crucial to identify the minimum node transmission power that will ensure network connectivity with high probability. It is known that there exists a critical level transmission power ...

In this dissertation we develop a class of bandwidth-efficient algorithms for information relaying in large-scale wireless ad-hoc networks. The settings we consider involve a single source communicating its data to a destination via the aid of low-power low-cost relay nodes. In its simplest two-hop relaying form, data directly broadcasted to the relays from the source are directly relayed to the destination through a shared fading channel. We assume that the relays employ decode-and-forward or amplify-and-forward preprocessing prior to forwarding their ...

CMAX and max-min zPmin are two packet forwarding techniques designed to save energy wireless ad-hoc networks. Their aim is to forward packets in such a way that the network's energy is conserved better than if they were forwarded along the path with the least count of hops (i e using the traditional forwarding technique). This master thesis compares the two energy efficient forwarding techniques against each other and, against a least-hop scheme. The comparison is made by simulation in static networks ...