Rainer Baumann

Bio: Rainer Baumann is an academic researcher from ETH Zurich. The author has contributed to research in topics: Ad hoc wireless distribution service & Wireless Routing Protocol. The author has an hindex of 8, co-authored 13 publications receiving 839 citations. Previous affiliations of Rainer Baumann include École Polytechnique Fédérale de Lausanne.

An evaluation of inter-vehicle ad hoc networks based on realistic vehicular traces

Abstract: Vehicular ad hoc networks (VANETs) using WLAN tech-nology have recently received considerable attention. The evaluation of VANET routing protocols often involves simulators since management and operation of a large number of real vehicular nodes is expensive. We study the behavior of routing protocols in VANETs by using mobility information obtained from a microscopic vehicular traffic simulator that is based on the on the real road maps of Switzerland. The performance of AODV and GPSR is significantly in uenced by the choice of mobility model, and we observe a significantly reduced packet delivery ratio when employing the realistic traffic simulator to control mobility of nodes. To address the performance limitations of communication pro-tocols in VANETs, we investigate two improvements that increase the packet delivery ratio and reduce the delay until the first packet arrives. The traces used in this study are available for public download.

Generic mobility simulation framework (GMSF)

Abstract: Vehicular ad-hoc networks with inter-vehicular communications are a prospective technology which contributes to safer and more efficient roads and offers information and entertainment services to mobile users. Since large real-world testbeds are not feasible, research on vehicular ad-hoc networks depends mainly on simulations. Therefore, it is crucial that realistic mobility models are employed. We propose a generic and modular mobility simulation framework (GMSF). GMSF simplifies the design of new mobility models and their evaluation. Besides, new functionalities can be easily added. GMSF also propose new vehicular mobility models, GIS-based mobility models. These models are based on highly detailed road maps from a geographic information system (GIS) and realistic microscopic behaviors (car-following and traffic lights management). We perform an extensive comparison of our new GIS-based mobility models with popular mobility models (Random Waypoint, Manhattan) and realistic vehicular traces from a proprietary traffic simulator. Our findings leverages important issues the networking community still has to address.

Routing metrics for Wireless Mesh Networks

Abstract: Routing in wireless mesh networks has been an active area of research for many years, with many proposed routing protocols selecting shortest paths that minimize the path hop count. Whereas minimum hop count is the most popular metric in wired networks, in wireless networks interference- and energy- related considerations give rise to more complex trade-offs. Therefore, a variety of routing metrics has been proposed especially for wireless mesh networks providing routing algorithms with high flexibility in the selection of best path as a compromise among throughput, end-to-end delay, and energy consumption. In this paper, we present a detailed survey and taxonomy of routing metrics. These metrics may have broadly different optimization objectives (e.g., optimize application performance, maximize battery lifetime, maximize network throughput), different methods to collect the required information to produce metric values, and different ways to derive the end-to-end route quality out of the individual link quality metrics. The presentation of the metrics is highly comparative, with emphasis on their strengths and weaknesses and their application to various types of network scenarios. We also discuss the main implications for practitioners and identify open issues for further research in the area.

HEAT: Scalable Routing in Wireless Mesh Networks Using Temperature Fields

Abstract: Existing unicast routing protocols are not suited well for wireless mesh networks as in such networks, most traffic flows between a large number of mobile nodes and a few access points with Internet connectivity. In this paper, we propose HEAT, an anycast routing protocol for this type of communication that is designed to scale to the network size and to be robust to node mobility. HEAT relies on a temperature field to route data packets towards the Internet gateways, as follows. Every node is assigned a temperature value, and packets are routed along increasing temperature values until they reach any of the Internet gateways, which are modeled as heat sources. Our major contribution is a distributed protocol to establish such temperature fields. The distinguishing feature of our protocol is that it does not require flooding of control messages. Rather, every node in the network determines its temperature considering only the temperature of its direct neighbors, which renders our protocol particularly scalable to the network size. We analyze our approach and compare its performance with OLSR through simulations with Glomosim. We use realistic mobility patterns extracted from geographical data of large Swiss cities. Our results clearly show the benefit of HEAT versus OLSR in terms of scalability to the number of nodes and robustness to node mobility. The packet delivery ratio with HEAT is more than two times higher than OLSR in large mobile scenarios and we conclude that HEAT is a suitable routing protocol for city-wide wireless mesh networks.

Routing Packets into Wireless Mesh Networks

Abstract: Wireless mesh networks are a promising way to provide Internet access to fixed and mobile wireless devices. In mesh networks, traffic between mesh nodes and the Internet is routed over mesh gateways. On the forward path, i.e., from mesh nodes to Internet nodes, for all mesh nodes only route information for one destination, the gateways, needs to be maintained. However, on the backward path from the Internet to mesh nodes, an individual route for every mesh node is required. In this paper we investigate protocols for backward path routing in wireless mesh networks. Using simulation experiments with realistic mobility patterns of pedestrians and cars in cities, we compare three protocols, each of which represents a routing protocol family: (i) AODV with an extension for mesh networks, a reactive routing protocol, (ii) FBR, a proactive routing protocol, and (iii) GSR, a source routing protocol. Our results indicate that FBR has the highest packet delivery ratio but is not scalable to the network size. The extended AODV seems to be neither scalable nor does it achieve a high packet delivery ratio. A good compromise is provided by GSR, which is the most scalable to the network size and still achieves a high packet delivery ratio.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The Self-Organizing Map

Abstract: An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

Vehicular Networking: A Survey and Tutorial on Requirements, Architectures, Challenges, Standards and Solutions

Abstract: Vehicular networking has significant potential to enable diverse applications associated with traffic safety, traffic efficiency and infotainment. In this survey and tutorial paper we introduce the basic characteristics of vehicular networks, provide an overview of applications and associated requirements, along with challenges and their proposed solutions. In addition, we provide an overview of the current and past major ITS programs and projects in the USA, Japan and Europe. Moreover, vehicular networking architectures and protocol suites employed in such programs and projects in USA, Japan and Europe are discussed.