Oliver Hahm

... A Wireless Multi-Hop Network Testbed for future mobile networks Mesut Güneş Oliver Hahm Kaspar Schleiser {guenes,hahm,schleiser}@inf.fu-berlin.de ... DES-SERT[6] provides an easy way to implement routing protocols independently from the underlying operating system. ...

Motivated by our experience from previous testbed-based studies, we discuss the performance of flooding based route discovery schemes. Based on an empirical case study, the limits of routing in IEEE 802.11 wireless multi-hop networks are highlighted. We show that the route discovery itself can already lead to problems even when there are no or few data flows.

ABSTRACT In this paper, we present the Smart Berlin Testbed as an infrastructure for experimental research on Smart City scenarios. As part of Smart Cities, applications will arise that build upon a variety of information sources and provide the user with near real-time information about the surrounding environment. An important role in this scenarios will be taken by wireless network infrastructures. They will function as interfaces to the users who connect with their smartphone or laptop to access the applications. Additionally, wireless and wired sensor networks are required to monitor the urban environment. The Smart City infrastructure needs to integrate these sensor networks and make them accessible and controllable for the applications. The set-up of the Smart Berlin Testbed is accomplished with the interconnection of two large wireless mesh and sensor networks in Berlin, namely the DES-Testbed at the Freie Universität Berlin and the HWL-Testbed at the Humboldt University Berlin. Together, both networks comprise 250 wireless multi-radio mesh routers and an amount of heterogeneous sensor nodes in the same order. We describe how we interconnect the testbeds via the Internet and the provided research possibilities resulting from the diverse network architectures. As a first experiment, we show results of a white space detection experiment that has been carried out in the Smart Berlin Testbed in order to assess the channel conditions at the testbed sites.

Abstract In this paper we present the DES-Chan framework for experimentally-driven research on distributed channel assignment algorithms in wireless mesh networks. The implementation process of channel assignment algorithms is a difficult task for the ...

ABSTRACT The Distributed Embedded Systems Testbed (DES-Testbed) is a hybrid wireless mesh and wireless sensor network that has been deployed at Freie Universität Berlin and was successively extended from November 2007 to December 2010. This technical report gives an overview of the current topology and the properties of the IEEE 802.11 wireless mesh network that is part of the DES-Testbed. The information that was gathered from an experimental study shall enable researchers to optimize their experiment scenarios, to support the evaluation of experiments, and to derive improved models of real world deployments. The differences of testbeds compared with simulation models and how to evaluate and filter the raw data are addressed. The focus of our study is an up-to-date description of the testbed state and to highlight particular issues. We show that the node degree, link ranges, and packet delivery ratios are not normal distributed and that simple means are not sufficient to describe the properties of a real world wireless network. Significant differences of the results from three channels are discussed. As last, the technical report shows that the DES-Testbed is an overall well connected network that is suited for studies of wireless mesh network and wireless mobile ad-hoc network problems.