Tatiana K. Madsen

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Based on ideas and methods of ergodic theory this paper presents a new approach investigating mobile ad hoc network connectivity. It is shown how to define and evaluate the connectivity probability of a mobile network where the position of the nodes and the link quality changes over time. This methodology is applied to the random direction mobility model.(More)
Mobile users typically experience better connectivity if their mobile device performs handover to an available WiFi network rather than using a cellular network. For a moving user the window of opportunity is limited and the timing of the handover is therefore crucial. In this work we propose two location-based look-ahead handover prediction algorithms that(More)
The paper presents a new approach investigating mobile ad hoc network connectivity. It is shown how to define and evaluate the connectivity probability of a mobile network where the position of the nodes and the link quality changes over time. The connectivity probability is a measure that can capture the impact of the node movement on the network(More)
Clustering is a fundamental mechanism to design scalable protocols for sensor networks. In this paper we advocate to use this clustering functionality to perform data aggregation and network formation. We investigate scenarios of event-driven sensor networks with high degree of spatial-temporal correlation. Our main focus relies on the cross-layered design(More)
In this paper we present a number of wireless measurements conducted on mobile phones usingWLAN IEEE802.11b/g in a multicast scenario. When designing efficient error recovery mechanisms for reliable multicast protocols, it is necessary to have good a understanding how channel errors occur and preferably to have a network model that describes these errors(More)
In this paper we propose a relay selection scheme which uses collected location information together with a path loss model for relay selection, and analyze the performance impact of mobility and different error causes on this scheme. Performance is evaluated in terms of bit error rate by simulations. The SNR measurement based relay selection scheme(More)
This paper presents a design for safe wireless communication solution to be used for data transmission to and from a Driver Machine Interface that is a part of a train control system. Introduction of a wireless interface can significantly simplify the maintenance operations of a DMI since no physical detaching and cabling of the component is required.(More)
The network connectivity is one of the important parameters for ad hoc networking, where the communication between nodes relies on the multihop links. It can have a significant impact on the system performance. Therefore, it is important to be aware of the network properties for the correct interpretation of simulation results. The paper shows how to define(More)
Floating car data (FCD) has been used to collect traffic state information from a set of individual vehicles. Vehicles are equipped with On Board Units (OBU) that collect different measurements and the vehicle position and transmit the data to a remote control center. In current implementations of FCD systems, vehicle fleets use cellular connections for(More)
The paper addresses performance modelling of safety critical Ethernet networks with special attention to in-car networks. A specific Ethernet/IP based in-car network is considered as use-case. The modelling is based on the analytical method Real-Time Calculus (RTC), providing hard bounds on delay and buffer utilization. We show how RTC can be applied on the(More)