Rolf Hager

MINT-a mobile Internet router

The mobility of portable computers and workstations is not transparent to users. They adjust to reduced services as long as they have no connection to a supporting infrastructure. The goal of the Walkstation project is to realize a user transparent mobile IP router (MINT) for wireless links (infrared and radio) operating at 1-10 Mbit/sec. For the study of user behavior and system characteristics, a campuswide testbed (ERIC) with 50-100 stations is planned to demonstrate the new solutions found in the Walkstation II project.Today, mobility of portable computers and workstations is not transparent to users. They adjust to reduced services as long as they have no connection to a supporting infrastructure. The goal of the Walkstation project is to realize a user transparent mobile IP router (MINT) for wireless links (infrared and radio) operating at 1-10 Mbit/sec. For the study of user behavior and system characteristics a campus wide testbed (ERIC) with 50-100 stations is planned to demonstrate the new solutions found in the Walkstation II project.<<ETX>>

Intelligent cruise control and reliable communication of mobile stations

The reliability of a short range packet radio network for mobile stations is investigated via the probability of a successful transmission. The instantaneous power of an interfering stations transmission is described by a Rayleigh distribution. The authors determine the distribution of cumulated interference power and the probability of a successful transmission, when the number of interfering stations is random and each station transmits only with probability p. Two lower bounds of increasing complexity are given. The authors evaluate these bounds for an intelligent cruise control system, when mobile stations are lined up in a traffic jam, and one approaching vehicle should be warned by the last member of the queue. >

The ODP trader functionality applied to the integrated road transport environment

The integrated road transport environment (IRTE) tries to accomplish road transport enhancements via dedicated applications. Key problem is the connection of different application components. Therefore open distributed processing (ODP) provides suitable concepts. The paper introduces a formal approach for a uniform analysis of service importers, exporters and interface matching based on an algebraic model. The concept aims in providing the management of distributed road transport informatics (RTI) applications.<<ETX>>

Network management in short-range mobile radio networks: Performance tuning optimizes collision behaviour

The authors evaluate several network management algorithms to increase the performance of short-range mobile radio networks concerning collision avoidance and reduction of collision duration measured in frames. It is shown that suitable choice of transmission power with independent antenna systems fulfils requirements of applications while increasing the communication performance. The evaluations are made by simulations of a three-lane unidirectional highway. It is shown that earlier investigations of optimal transmission ranges are not satisfactory compared to the requirements of applications.<<ETX>>

Analysis of mobile packet radio networks in Rayleigh fading environments

In this paper, we consider a Rayleigh fading channel for mobile radio networks. The distribution of cumulated instantaneous interference power is determined when interfering stations are located at random. The corresponding distances from a reference station are represented by a (deterministically delayed) renewal process with finite horizon. This distribution serves as a basis for determining the probability of successful transmission. We start with a short survey on existing models in the literature. >

Feasibility-study of a multiplexing strategy in road transport informatics for short range MRNs

Several different strategies for statistical multiplexers are investigated and compared by means of simulation in a real-time environment. According to special applications in the field of road transport informatics in short-range mobile radio networks (SR-MRNs), the different message types and their characteristics (e.g., arrival rate, real-time, amount of data, etc.) are described. A novel adaptive priority-oriented multiplexing algorithm called APS (adaptive priority scheduling) is examined with respect to its behavior in comparison to common strategies. The efficiency of APS compared with common strategies depends on the applications and their traffic load. APS never reduces the system performance, and, if several applications with hard time constraints have to be served simultaneously, APS will increase the performance.<<ETX>>

Light-weight application layer architecture for short-range communication networks

This paper focuses on the application layer architecture for dedicated short range communication (DRSC) networks. The current state-of-the-art in the development of layer 7 structures and related objects Is presented. Exemplary methods of DSRC management are explained.<<ETX>>

Security Management — An Overview to Reliable Authentication Procedures for Automatic Debiting Systems in RTI/IVHS Environments

The research and development in the area of short-range mobile radio networks have produced a new kind of applications and profiles of communication systems. With the concepts “Road Transport Informatics” (RTI) and “Intelligent Vehicle Highway Systems” (IVHS) much effort has been undertaken to develop and standardize mobile communication systems. In particular, the European projects PROMETHEUS and DRIVE and the American equivalent IVHS are promoting new technologies.

Fault management of infrastructure networks

An approach for suitable fault management in traffic information networks, focusing on the isolation of network faults in infrastructure networks, is introduced. The authors show, that model-based diagnosis is an efficient method for finding explanations consisting of the underlying fault events of system failures. A fault management system based on these concepts is discussed and evaluated.<<ETX>>

Fehlermanagement in Verkehrsinformationsnetzen

In this paper, an approach to fault management in traffic information networks to isolate network faults in infrastructure networks will be introduced. We will show, that model-based diagnosis is an efficient method for finding explanations consisting of the underlying fault events of system failures. A fault management system based on these concepts will be discussed and evaluated.