Research at Chair for Communication Networks Bernhard Walke. Head of Communication Networks Research Group

Transcription

1 Research at Chair for Communication Networks Bernhard Walke Head of Communication Networks Research Group Research Report 2012

2 Talk at inauguration of ComNets building at Nov. 21, RWTH Aachen University Rectorate names the building Bernhard-Walke-Haus. Vice Rector Prof. Schuh and Dean Prof. Hameyer (right) uncover the ComNets Routing Post to Prof. Walke and his wife.

3 Preface At the occasion of celebrating switch of status from Full Professor to Professor Emeritus in July 2007, my staff donated me a booklet that it had carefully prepared, titled Traces of Scientific Research Supervision by Example of Com- Nets Doctoral dissertations. The booklet is a compilation of my abstracts of the doctoral theses that I had supervised so far at RWTH Aachen University, and photos are added to remember of the respective students. As a main actor behind compiling the booklet mentioned, Dr. Reinhold Gebhardt, senior staff member at ComNets, proposed in 2012 to compile a Research Report on work performed under my guidance spanning my time at FernUniversity of Hagen, Germany ( ) and at RWTH Aachen University, Germany ( ). The idea was to value the work done and relate it to the progresses in the field of communication networks. This report serves to highlight the contributions made to the state of the art by about 75 Doctoral dissertations (4950 man months) that are the result of excellent cooperation with my Doctoral students. The Doctoral dissertations in part represent the findings contained in 778 Diploma-/Masters theses and 336 Student-/Bachelor theses performed at ComNets during that were performed under shared supervision by myself and the respective Doctoral student. This workforce represents an equivalence of 886 man years. Although we have published our research results in many scientific journals and conferences and have published six English books on mobile radio networks, no document exists so far explaining our research motivations, the interrelationship of the various research domains covered and to name the most important of more than 130 funded research projects run at ComNets over the years. One main goal of the Report is to name the key innovations resulting from our work. Another goal is to name the most cited publications and related ComNets authors that helped to establish ComNets as a brand for scientific research in wireless and mobile radio network protocols and services. May this report proof useful for the readers! Aachen, September 30, 2012 Bernhard Walke

4 ComNets, RWTH Aachen University residence ComNets-Walke Emeritus kick off ; start of ComNets Research Group

5 Contents 1 History Start in September Communication Networks - ComNets Research Experience ported from Hagen Cellular Radio Licensing Decisions Experiences from Industry Carreer Purpose of this Research Report 4 2 Key Achievements of Research Research Domains Revolutionary achievements Evolutionary Achievements 7 3 ComNets and Faculty ET & IT Diploma-/Masters Theses at ComNets ComNets Recognition in the Faculty ET&IT Endowed Chair Mobile Networks ComNets Succesorship Umic Excellence Cluster ComNets pulled out from UMIC ComNets Research Group ComNets Graduate Students Fund ComNets Alumni Circle ComNets Brand 16 4 Research Domains Acknowledgment Research Goals in Inaugural Lecture General Remarks nd Generation Cellular Radio Handover Studies GPRS, A Service in GSM Trunked Cellular Mobile Radio Network rd Generation Cellular Radio Introduction 26

6 4.6.2 UMTS research at ComNets Wireless ATM, HiperLAN/2, WiMAX Introduction Wireless Broadband Systems MAC Frame of 4G Systems HiperLAN/2, Pre-decessor of LTE/LTE-A HiperLAN/2 Ad-Hoc Network IEEE WiMAX th Generation Cellular Radio EU-WINNER Projects Dynamic Channel Assignment for Cellular Fundamentals of OFDM Systems VoIP Capacity of LTE Systems Multi-hop Relay Enhanced Cells Multi-hop Relays Heterogeneous (multi-mode) Relays Capacity of Relay-Enhanced Cells Mobile Satellite Systems Introduction Geostationary Satelites Low Earth Orbit (LEO) Satellites UMTS Satellites Cordless Telecommunication System DECT DECT in the Local Loop Spectrum Requirements for Mobile Radio Protocols/ Services in Telco Networks Universal Personal Telecommunications Intelligent Communications Manager CAMEL für UMTS Agents in Telecommunication Networks Electronic Commerce and Security Web Services for Mobile Data Applications Mobile WEB Server Platform Stochastic Event-Driven Simulation Correlated Samples Confidence Interval Fixed Network Planning Local Area Networks and Project IEEE Multi-Hop Ad-Hoc Networks 68

7 Multi-Hop Networks with QoS Support QoS to WLAN IEEE by ComNets HiperLAN/2 Ad-Hoc Network Cognitive Radio for WLAN Coexistence Multi-Carrier CDMA for IEEE WLAN Cellular Radio to WLAN Interworking Mesh Distributed Coordination Function Multimedia Service for Spotty WLANs Wireless Mesh IEEE Proposals QoS for IEEE 802 WLAN/WPAN Systems Voice over IP Capacity for IEEE Vehicle-to-Vehicle/Infrastructure Comms Dedicated Short-Range Communication ABMT-Series for Doctoral Dissertations Dissertations ordered by Publication 86 5 Publications by Doctoral students Foreword Aijaz, Fahad Becker, Christian Berlemann, Lars Bjelajac, Branko Böhmer, Stefan Brasche, Götz Philip Brass, Volker Bültmann, Daniel Einhaus, Michael Decker, Peter Esseling, Norbert Farjami, Peyman Forkel, Ingo Fornefeld, Ulrich Fröhlich, Hanno Matthias Gehlen, Guido Geulen, Eckhard Göbbels, Stephan Görg, Carmelita (Habilitation) Guntermann, Martin 107

8 5.22 Guntsch, Alexander Gotthardt, Klaus Habetha, Jörg Hartmann, Jens Heier, Silke Hellmich, Thomas Herrmann, Christoph Herwono, Ian Hettich, Andreas Hiertz, Guido R Hoymann, Christian Hußmann, Holger Irnich, Tim Jennen, Ralph Junius, Martin Kadelka, Arndt Kennemann, Olrik Klagges, Karsten Kleier, Stephan Klein, Ole Krämling, Andreas Kriengchaiyapruk, Tham Lawniczak, Damian R Lott, Matthias Luo, Jijun Malkowski, Matthias Mangold, Stefan Max, Sebastian Mende, Wolf Mirkovic, Jelena Obradovic, Vladimir Oh, Seong-Hoon Orfanos, Georgios Otyakmaz, Arif Pabst, Ralf Peetz, Jörg Petras, Dietmar Plenge, Christian 130

9 5.60 Rapp, Jürgen Shahbaz, Mohammad Scheibenbogen, Markus Schieder, Andreas Schinnenburg, Marc Sievering, Peter Schoenen, Rainer Schultz, Daniel Siebert, Matthias Speetzen, Alexander Steffan, Herbert Steppler, Martin Stibor, Lothar Stuckmann, Peter Tomaszewski, Hans-Jürgen Vornefeld, Ulrich Walke, Bernhard Weiss, Erik Wietfeld, Christian Wijaya, Harianto Xie, Zheng Xu, Bangnan Zang, Yunpeng Zhao,Rui Zhu, Wei Patents and Patent Applications Introduction List of Patents and Applications Appendix Publications cited at least 20 times 157 Curriculum Vitae 172 Index 174

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11 1 History ComNets, RWTH Aachen University residence Start in September 1990 Communication Networks (ComNets), a chair in the Faculty of Electrical and Information Engineering at RWTH Aachen University, Germany, started in autumn At that time, research and teaching responsibility was hand-over to me from my predecessor Prof. Dr.-Ing. Friedrich Schreiber. He was the Chair for General Electrical Engineering and Remote Data Processing Schreiber s chair (and its staff) had a name for contributions to performance evaluation of computer communication networks, based on probability theory, stochastic Friedrich Schreiber processes, queuing theory, theory of scheduling and event driven system simulation. Besides contributions to the performance analysis of single server systems under sophisticated scheduling disciplines, Bayes statistics have been applied in rare event system simulation for, precisely, specifying the statistical uncertainty of results of simulation experiments with correlated samples. 1.2 Communication Networks - ComNets In June 1989 the Faculty had decided Traffic Theory to be crucial for its 1

12 History Technical Computer Science curriculum (1) and, accordingly, had invited me to be the successor to Friedrich Schreiber. I focused research and teaching at the chair named in 1991 Communication Networks (ComNets) to cover design besides performance evaluation of real world communication systems like ISDN and ATM networks, wireless multi-hop networks and mobile radio systems and also established a group on formal specification of protocol software. Accordingly, from the initial we continuously participated in projects devoted to the exploitation of the progress in wired and wireless transmission techniques to agree on architectures for advanced communication networks and soon were Bernhard Walke a well-accepted partner in the respective standardization and standards preparing organizations. Over the years, our contributions to the performance-aware design of wireless and mobile radio networks protocols made ComNets unique in the discipline, beyond Europe. Accordingly, we had funds to employ, on full research assistant positions, on average 35 graduate students mostly working on research projects, aiming towards a doctoral degree. 1.3 Research Experience ported from Hagen When joining RWTH Aachen University, I had a seven years experience in research and teaching as a chair for Data Processing at the Faculty of Electrical ComNets Internet Representation and Electronic Engineering, Fern- University Hagen, Germany and had published course books on data processing techniques and traffic theory for real-time computer systems. There, my group of about six doctoral students had its focus on design and performance evaluation of self-organizing mobile multi-hop communication networks intended, besides others, for road transport telematic systems. And, I had experience with research fund raising from national and European government and from in- 1 Norbert Gilson, Walter Kaiser: Elektrizität Energie Information; Die Geschichte der Fakultät Elektrotechnik und Informationstechnik an der RWTH Aachen, Diepholz GNT-Verlag, Stuttgart 2010, Seite 137 2

13 Experiences from Industry Carreer dustry, already. After joining RWTH Aachen University, research projects and related technical equipment were moved from Hagen to Aachen and the research was widened. 1.4 Cellular Radio Licensing Decisions At Fern-University of Hagen in 1988/89 under contract to the Minister of Post and Telecommunication, Germany, my team (together with two other teams of the same university) evaluated the Technical Annexes of ten applications for getting the license to operate what is known today as the Vodafone D2 network in Germany. The Ministry followed the recommendation by the Hagen evaluation group (2). In 2003/2004 at RWTH Aachen University I served to the same Minister to resolve a tie resulting from adverse recommendations by two technical evaluation groups that had evaluated applications to get the license to operate what is known today as E-Plus network in Germany. The Minister followed my recommendation. Both operators Mannesmann Mobilfunk (now Vodafone D2) and E-Plus, thanks to my role in the respective decision processes, owe me their business. I have kept this confidential until now. 1.5 Experiences from Industry Carreer Before joining Fern-University Hagen, I had an eighteen years experience in several roles in industry, mainly in the Telefunken (later AEG-Telefunken) Research Institute Ulm, which is now part of EADS, where I worked towards my doctor s degree and gained my experience on design of complex computer and communication systems that I later in my university career benefitted from. In industry, besides others I became an expert for trunked mobile radio systems (e.g. TETRA) and developed the multi-hop packet radio network that was further refined later under industry contracts at Hagen and Aachen. Our multi-hop expertise helped us to be (under Philips sponsorship) a major actor in IEEE Mesh standardization, and this was the root wherefrom we developed the concept of relay-enhanced cells that is now part of standard 3GPP LTE-A. 2 Evaluation of applications to the Ministry to get the license was an anonymous process. My professor colleagues in our evaluation group wanted to exclude one application (that later turned out to be Mannesmann AG) from the technical evaluation because lacking credibility of the statements made, which I did not agree to. The other technical evaluation group contracted by the Minister had ranked Mannesmann far down on its priority list of consortia to be recommended to be licensed. 3

14 History 1.6 Purpose of this Research Report This report intends to describe the most important ComNets research areas and related key research achievements made. Staff members are named together with their most cited publications and their work is set in context to the state-of-art in the discipline. At the time of writing this report (September 2012) 108 scientific Com- Nets publications have reached more than 19 scholar.google citations out of about ComNets publications in total, including 55 patents. Other purposes of this report are to Name major ComNets projects and their most important contributions to the state-of-art. Name research areas, where ComNets staff generated world-class contributions Present Summaries of all doctoral theses resulting from ComNets project work. ComNets has published six Annual Reports, each covering a two years period, starting from 1990 until People interested in details like funding agencies, subjects of projects, involved people, and temporal research topics may wish to visit h t t p : / / w w w. c o m n e t s. r w t h - a a c h e n. d e / p u b l i c a t i o n s / a n n u a l - r e p o r t s / j u l f e b h t m l Five reports (1992, 1994, 1996, 1998, 2002) are available for download (the first exists as hardcopy only in the ComNets library). Especially, the first chapters of the reports including the Research Overview on the reporting period may be of interest. A reader of the book may wish to step through the text reading the introductions to the chapters and sections, only. Thereby, a good overview on the technical challenges in mobile systems research and the main contributions by ComNets to support the exponential growth of cellular and wireless can be gained. 4

15 2 Key Achievements of Research 2.1 Research Domains ComNets Crew 2003 Each doctoral dissertation discussed later, of course, is a contribution to improve the state-of-the-art and we have kept very high quality standards. The ComNets group had a very broad thematic coverage of research areas including radio propagation and mobile receiver modeling, mobile and fixed network planning, design of wireless/mobile and fixed network protocols, traffic performance evaluation based on mathematical analysis and stochastic event driven simulation, theory of scheduling of scarce resources, further development of analysis and simulation techniques, application of formal specification techniques for protocol software prototyping, fuzzy logic and game theory, design and prototypical implementation of multi-media services. And these areas have been applied in the context of real telecommunication networks like ISDN, ATM, GSM/GPRS, UMTS, TETRA, DECT, LTE, Internet and many kinds of IEEE 802.xx systems. By doing so we have generated a very positive response by industry researchers that in numerous cases adopted our solutions to be used in their products. In the following the most important achievements by ComNets are named. The criterion for naming 5

16 Key Achievements of Research a result a key achievement are the impact the results had on the standardization and implementation in real systems, and the number of citations of related publication. h t t p : / / w w w. c o m n e t s. r w t h - a a c h e n. d e / f l e a d m i n / f o r s c h u n g / C o m N e t s _ A c h i e v e m e n t s _ _ 0 1. p d f classifies our main achievements as revolutionary and evolutionary achievements, respectively. 2.2 Revolutionary achievements Development of the access protocol functions and of the protocol stack family of GPRS: We claim to be the enablers of GPRS and, thereby, of the Mobile Internet (1). Our respective papers have not gained much attention, since they were published as ETSI contributions, accessible to the ETSI membership only. We were the first (2) to describe and analyze the traffic performance of GPRS, gaining 375 scholar.google citations. A Development of the medium access control (MAC) protocol data unit format used for the radio resource control of both, wireless and mobile broadband systems in standards ETSI/BRAN HiperMAN, IEEE WiMAX IEEE m mobile broadband WiMAX, 3GPP LTE/LTE-A mobile broadband. In mobile broadband systems control information for multiple mobile stations must be communicated downlink in a given MAC frame, otherwise radio resources are wasted. Our concept (3) that has gained 85 scholar.google citations is now applied in all modern mobile broadband systems, worldwide, without any exception. B Introduction of fixed decode & forward relays for cellular (4). Our origi G. Brasche, B. Walke: Concepts, Services, and Protocols of the new GSM Phase 2+ Gerneral Packet Radio Service. In IEEE Communications Magazine, p. 94, New York, USA, 08/ B. Walke, D. Petras, D. Plassmann, Wireless ATM: Air Interface and Network Protocols of the Mobile Broadband System,IEEE Personal Communications Magazine, Vol. 3, 50-56, 08/ N. Esseling, H.S. Vandra, B. Walke, A Forwarding Concept for HiperLAN/2. Proc. European Wireless Conference, 09/2000, 13-18,, Dresden, Germany w w w. c o m n e t s. r w t h - a a c h e n. d e / p u b l i c a t i o n s / g e s a m t l i s t e n / a b s t r a c t s / / e s v a w a - e w h t m l 6

17 Evolutionary Achievements nal paper (5) gained 28 and a later paper with three ComNets authors in front of the author s list gained citations. The concept applicable to ISO/OSI layers 2 and 3 is standardized for all 4th generation mobile broadband networks, e.g. IEEE WiMAX, 3GPP Rel. 8 (LTE), 3GPP Rel. 10 (LTE-Advanced). Compared to legacy cellular radio networks, the spectral efficiency can be doubled with this concept or the area covered by a base station can be increased four to ten times. C We developed (6) the radio access protocol for the Dedicated Short Range Communication (DSRC) system used for Electronic Fee Collection at 5.8 GHz according to Standard EN15509, which is used world-wide. The Toll Collect system of Germany, is the only remarkable exemption in the world for an electronic fee collect system not following this standard. The related research community is quite small so that we gained 14 citations, only. D Our expertise in multi-hop packet radio networks enabled our key contributions (7) to standards IEEE e (Mesh). For a related paper we gained 640 citations, for another one (8) 370 citations. 2.3 Evolutionary Achievements A ComNets authors (9) proposed the analytical model and algorithm to calculate the spectrum demand of 4th generation radio systems. The paper gained 15 citations. The EU-WINNER 2 project developed our algorithm to become a method that was named standard ITU-R Rec. M.1036 Spectrum Estimation Methodology. A related book (10) gained 22 citations. Based on our algorithm and the WINNER2 method, World Radio Conference, Geneva 2007 calculated the spectrum demand and 5 Pabst, B. Walke, D. Schultz, et al, :Relay-Based Deployment Concepts for Wireless and Mobile Broadband Radio. In IEEE Communications Magazine, p.p , New York, US, 09/ G. Brasche, C.H. Rokitansky, C. Wietfeld: Communication architecture and performance analysis of protocols for RTT infrastructure networks and vehicle-roadside communications, 44th IEEE Vehicular Techn. Conf., Stockholm, Sweden, 06/1994, S. Mangold, S. Choi, O. Klein, G. Hiertz, L. Stibor: IEEE e Wireless LAN for Quality of Service (invited paper). In Proceedings of the European Wireless, Vol.1, p.p , Florence, Italy, 02/ S. Mangold, S. Choi, G.R. Hiertz, O. Klein, B. Walke: Analysis of IEEE for QoS Support in Wireless LANs. In IEEE Wireless Communications, Vol.10, p.p. 2-12, 12/ T. Irnich, B. Walke: Spectrum Estimation Methodology for Next Generation Wireless Systems. Proc. IEEE PIMRC 2005, Berlin, Germany, 09/ H. Takagi, B. Walke: Spectrum requirement planning in wireless communications: Model and methodology for IMT-Advanced, John Wiley & Sons Inc 7

18 Key Achievements of Research assigned 480 MHz of bandwidth for 4th generation mobile systems. B Wireless Personal Area Networks (WPAN) is an alternative to WLANs for wireless broadband communications. Our MAC protocol design (11) that gained 15 citations, is the key of the standards: ECMA 368 (WiMedia/MBOA), ISO/IEC 26907, ETSI TS V1.1.1, ECMA 387 C Two papers on software defined protocol stacks (12) to enable multi-mode protocols (13) gained 18 and 11 citations, respectively. D We have been the first to describe and implement Mobile WEB Services for P2P communications (14) ; a related paper gained 58 citations, another one (15) 20 citations. This technology may change the architecture of smart phones and may widen its application. E Our continuous work in developing realistic event driven system level simulators for wireless and mobile systems resulted in the public domain code (LGPL license) of the Wireless Network system Simulator openwns released in March 2009 (16) cited 25 times so far. It covers systems according to standards IEEE a, b, g, e, n, s, IEEE d, e, j, m, 11 G. Hiertz, Y. Zang, J. Habetha, H. Sirin: Multiband OFDM Alliance The next generation of Wireless Personal Area Networks. Proc. IEEE Sarnoff Symposium, Princeton, New Jersey, USA, 04/ M. Siebert, B. Walke: Design of Generic and Adaptive Protocol Software. Proc. 3G Wireless and Beyond 01, San Francisco, USA, 06/ L. Berlemann, R. Pabst, B. Walke: Efficient Multi-Mode Protocol Architecture for Complementary Radio Interfaces in Relay-Based 4G Networks. IEEE Wireless Communications, 06/ G. Gehlen, L. Pham,: Mobile Web Services for Peer-to-Peer Applications. In Proceedings of the Consumer Communications and Networking Conference 2005, p. 7, Las Vegas, USA, 01/ F. Ajaz et. al.: Enabling high performance mobile web services provisioning. Proc. IEEE 70th FAll VTC Conference 2009, Sep D. Bültmann, M. Muehleisen, K. Klagges, M. Schinnenburg: openwns open Wireless Network Simulator. Proc. 15th European Wireless, Aalborg, Denmark, 05/2009, , 8

19 Evolutionary Achievements 3GPP LTE / LTE-A The openwns Simulator was also used to evaluate ITU-R IMT-A candidate systems in the WINNER+ project and was calibrated for that purpose by other simulators. Besides this application oriented research we also contributed fundamental research findings to progress the state-of-the-art in information engineering. The respective achievements are described in Chapter 4. It is worth noting that we at ComNets engaged very much in porting information on the new developments to students and to the public, in general, by writing monographs and textbooks that were published mostly by the worldwide well-accepted publisher John Wiley & Sons, UK. The authors, titles and contents of the books are available from the right hand column in Since we continously updated our lectures to students we had a very positive response by students, see section 3.1 The 900 pages book Mobile Radio Networks (2002) written by ComNets authors reached 437 citations. Book Cover The most important (English) book publications by ComNets can be found under 9

20 The Beast served since 2005 as Simulation Computer 10

21 3 ComNets and Faculty ET & IT ComNets Crew Diploma-/Masters Theses at ComNets Starting from September 1990 until December 2012, a number of 778 Diploma-/Masters theses and 336 Study-/Bachelor theses have been written by students working in ComNets labs. The Diploma thesis of a student is equivalent to a Master thesis, namely research in a subject agreed between a ComNets research assistant and myself to be worked at full-time during six months in the ComNets labs. A report and oral presentation of the thesis concludes the student s work. My model of supervision of Diploma-/Master theses was as follows: Agreement between myself and a ComNets research assistant on the subject of the thesis and proposition to the student in form of a written specification of the work to be done, including references to prior art to be started from and tools to be used. Intermediate reports are given to me by the student in presence of the responsible research assistant every two months during a min. meeting in my office based on Power Point slides. The current progress and directions for the future work are discussed in the meeting. Final Power Point based presentation of the main results of the thesis (20 min) and discussion of the results in the public ComNets Seminar. 11

22 ComNets and Faculty ET & IT The grade for the thesis, typically, was fixed within two days after the oral presentation. In total 778 Diploma- and Master theses have been supervised at Com- Nets during 1991 to 2012, an average number of 37 theses per year. When compared to the total number of finalists per year in the Faculty, about 20-25% of all students performed their Diploma/Masters thesis at ComNets. In addition, in total 399 Study- and Bachelor theses have been supervised, an average of 19 theses per year. Most of the workforce contributed by Diploma/Master theses went into the development of software based tools for the modeling and performance evaluation of fixed and mobile communication networks. The Diploma/Masters performed at ComNets in are listed under and more recent theses are stored in digital form. Access to theses is for free for the membership of FFV, the ComNets Friends and Supporters Community. 3.2 ComNets Recognition in the Faculty ET&IT The ComNets Chair, according to faculty-internal algorithms in the years was a most prominent unit in both, number of research publications and amount of external funds. Even in the category Teaching, Com- Nets was above average. 3.3 Endowed Chair Mobile Networks The Chair of Mobile Networks had been established as an endowed chair in the Faculty on my initiative to complement the ComNets research areas in 2002 from a five years grant by Ericsson AB, and became a regular chair in the Faculty funded by RWTH Aachen University in As the head of the finding committee I cared for winning a colleague (Petri Mähönen) with an expertise, mostly orthogonal to the expertise present in ComNets. 3.4 ComNets Succesorship Since the candidates ranked on the first ComNets successorship list established in 2004 by the Faculty denied to become the successor, I agreed to continue service until 7/2006, one year beyond my retirement date. The Faculty in 2005 supported my proposal to raise a research & teaching building for about 3.3 Mio paid from resources on the ComNets accounts. At inauguration of the building in autumn 2008 it was named by the Vice Rector Prof. Günter Schuh (on initiative by the Dean of the Faculty, 12

23 Umic Excellence Cluster Prof. Kay Hameyer) Bernhard-Walke-Haus and the ComNets Research Group moved in. The second candidate list for ComNets successorship established by the Faculty in 2006 did not result in any negotiations between a candidate and the university administration. Instead, finding commission members proposed to search for better candidates from overseas. No new candidates were found and no progress was made in 2006 to During this time the Faculty refused to establish a research professorship to head the 25 doctoral students at ComNets. With substantial support by the Rectorate of the RWTH Aachen University under Rector Prof. Burkhardt Rauhut I continued service for ComNets during that time. During this interim period I acted at ComNets as if in office. New projects were started and staff hired. The scientific productivity continued as before: In 2008/2007/2006/2005 ComNets published 34/29/29/29 scientific papers (in total 121 papers in four years, of which 16 and 9 papers, respectively, gained more than 20 and 30 scholar.google citations. In 2009 the Faculty followed recommendation by members of the former finding committee to name Petri Mähönen, chair of Mobile Networks in the Faculty, the ComNets successor and to close the Mobile Networks chair. Accordingly, the former Mobile Networks staff was enriched by ComNets staff positions, the new unit renamed to Institute of Networked Systems (INETS), and part of ComNets scientific staff positions reassigned to other chairs. In doing so the Faculty discontinued support to ComNets which at that time was one of the most succesful units in the faculty. At the same time the worldwide known ComNets brand was extinguished. Although it was agreed with the Faculty to host mobile radio research in the Bernhard-Walke-Haus, it is now housing time-wise homeless groups from outside the Faculty during renovation of their respective office space, and partly the building is unused. There are plans in the Faculty to move the chair for Technical Acoustics in 2013 to this building. 3.5 Umic Excellence Cluster In 2004/05 the so-called Exzellenz Initiative started in Germany offering universities, besides others, to apply for a five years funding of an Excellence Cluster to get funds in an amount of about 6.5 Mio per year. 13