Raphael Ernst

BonnMotion: a mobility scenario generation and analysis tool

Simulation and emulation are techniques frequently used for performance evaluation of wireless multi-hop networks. If the wireless devices are mobile, the movement patterns of these objects are found to have significant impact on the simulation and emulation results. This is quite obvious as the movements influence the topology of the network. In this paper we describe and present BonnMotion. BonnMotion is an open-source Java software which creates and analyzes mobility scenarios. It has been developed at the University of Bonn, Germany, where it serves as a tool for the investigation of mobile multi-hop network scenario characteristics. The scenarios can also be exported for the network simulators ns-2, GloMoSim/QualNet, COOJA, and MiXiM.

Adaptive HELLO for the Neighborhood Discovery Protocol

In typical Mobile Ad-Hoc Network (MANET) applications, the network topology changes frequently due to device movement, or link failure. Consequently, a fast response to connectivity changes is one of the most important challenges in MANETs. Most proactive routing protocols detect changes by exchanging control messages. The Neighborhood Discovery Protocol (NHDP) specifies the exchange of these kind of messages. As shown in prior studies, the proposed fixed intervals of NHDP cause unnecessary protocol overhead or late link detection. Our Adaptive HELLO (AH) scheme adapts the interval dynamically with respect to the actual situation and coordinates it between the nodes when necessary. The result is a fast link change detection and an overhead reduction in certain scenarios.

Indoor mobility modelling

For the simulative and emulative performance evaluation of tactical indoor communication systems modeling mobility is an important task. Typical assumptions are a uniformly distribution of destinations, shortest paths movement without obstacles, and randomly chosen speeds. These assumptions do not hold for tactical indoor scenarios. In this paper, we introduce a new rule-based indoor mobility model for tactical scenarios. We show that the realistic modeling has a great impact on the evaluation of routing protocols. Furthermore, we demonstrate that even complex movements can be represented by small rulesets.

Poster: Deploying a mesh-based command and control sensing system in a disaster area maneuver

Wireless multi-hop networks meet the requirements of disaster area scenarios by their definition. Recently, different mesh and Wireless Sensor Network (WSN) testbeds were deployed. However, these deployments do not meet the specific characteristics of disaster area scenarios. Developing algorithms and protocols for public safety scenarios and deploying public safety networks is a huge challenge. We have developed BonnSens a commercial off-the-shelf (COTS)-based prototype of a mesh-based command and control sensing system for public safety scenarios. In this poster, we present experiences as well as first measurement results from an on-site deployment in a disaster area maneuver. Overall, our goal is to see which approaches are applicable for public safety networks and where further specific challenges are.

Optimizing ODMRP for underwater networks

Underwater networks have attracted significant attention over the last few years. They can be used in scenarios like environmental monitoring and mine countermeasure but may also be part of modern marine warfare. A prominent example is Anti Submarine Warfare (ASW) with multistatic sonars. These networks may be sparse with potentially long distances between single nodes such that direct communication is not always possible. Furthermore, long propagation delays and shadowzones have a negative impact on the communication channel. A solution to overcome these challenges is to realize a multi-hop network by using ad-hoc routing. A well known protocol from terrestrial networks is the On-Demand Multicast Routing-Protocol (ODMRP). In this paper, we present an optimization for ODMRP, named Route-Discovery-Suppression, to improve its performance for the deployment in underwater networks. We evaluate the performance through simulations in different scenarios and show its impact in comparison to other routing protocols.

Evaluation of wireless multi-hop networks in tactical scenarios using BonnMotion

Simulation and emulation are techniques frequently used for performance evaluation of wireless multi-hop networks. If the wireless devices are mobile, the movement patterns of these objects are found to have significant impact on the simulation and emulation results. This is obvious as the movements influence the topology of the network. In this paper, we focus on the sound performance evaluation of wireless multi-hop networks in tactical scenarios. In detail, we address the modeling of specific scenarios. We show the impact of proper modeling in disaster area and urban warfare scenarios. By doing so, we show how the tool BonnMotion can help other researchers in mobility dependent research.

Extending ODMRP for on-site deployments in disaster area scenarios

One of the primary application scenarios for mobile wireless multi-hop networks are disaster areas. However, these pose specific challenges for routing, such as mobility and highly unpredictable links. The main applications for disaster area networks - group-based voice communication and group-oriented, map-based tracking - can be realized using multicast groups. Thus, we decided to implement ODMRP for disaster area deployments. In several disaster area maneuver on-site deployments, we identified the need for extensions, making the protocol more suitable for real-world deployments. In this paper, we propose three extensions to ODMRP: (1) link quality based routing, (2) prioritization of control messages, and (3) overhead reduction mechanisms. In simulations as well as in real-world measurements, we show the benefit of the extensions proposed.

Distributed and Collaborative Malware Analysis with MASS

Malicious software poses a great risk to critical infrastructure. Researchers have proposed numerous ways to analyze malware behavior in order to understand and respond to this threat. However, only little attention has been paid to the organization of the malware analysis process itself. In this paper we present the Malware Analysis and Storage System (MASS), a novel framework for malware analysis. MASS is designed as a distributed and scalable system and aims to empower cooperation between malware researchers. We will describe the central aspects of the framework and explain the malware analysis process flow. Furthermore, we will present a performance evaluation to demonstrate the suitability of the framework for typical malware analysis tasks.

Reducing MANET neighborhood discovery overhead

Routing in MANETs still is a challenging task. Especially for proactive protocols where nodes periodically send control messages, a vast amount of the available data rate is used for link detection and the dissemination of topology information. Numerous enhancements to existing routing protocols to reduce the overhead caused by control messages have been proposed. Most of them use complex algorithms or keep track of previous messages. Due to the complexity and sometimes requirements for special hardware or information sources, none of these extensions are widely used. Therefore, we propose two extensions which are simple to implement yet provide significant overhead reduction for typical control messages. The first extension removes unnecessary bytes and redundancy from control messages. The second extension introduces smaller messages sent as replacements when the information did not change since the last message. Both extensions can be used in parallel or individually, providing a good amount of overhead reduction while being simple to implement and integrate.

Measuring and modeling performance of WLAN communication for multistatic sonar applications

It is known that the accumulated contact data of all stations of multistatic sonar arrays cannot be handled by traditional VHF links. While other technologies like satellite communication systems could handle the amount of data, these systems are usually too costly in terms of money, weight, or power consumption to be deployed on sonar buoys. Therefore, we installed commercial off-the-shelf WLAN with 4W boosters on a vessel and buoys and measured the achievable communication ranges and data rates during a sea trial. With our experiments we were able to reach ranges of 10km and beyond. Afterwards we derived functions and parameters from our measured data to help predicting the WLAN performance for similar scenarios.