Papers by Laurent Schumacher
Securisation of SIP Presence notifications thanks to the Belgian electronic identity card
The 2007 International Conference on Next Generation Mobile Applications, Services and Technologies (NGMAST 2007), 2007
Performance evaluation of indoor Internet access over a test LTE mini-network
2011 the 14th International Symposium on Wireless Personal Multimedia Communications, 2011
A stochastic MIMO radio channel model with experimental validation
Ieee Journal on Selected Areas in Communications, Sep 1, 2006
Theoretical and experimental studies of multiple-input/multiple-output (MIMO) radio channels are ... more Theoretical and experimental studies of multiple-input/multiple-output (MIMO) radio channels are presented. A simple stochastic MIMO model channel has been developed. This model uses the correlation matrices at the mobile station (MS) and base station (BS) so that results of the numerous single-input/multiple-output studies that have been published in the literature can be used as input parameters. The model is simplified
Link-level access cloud architecture design based on SDN for 5G networks
Ieee Network, Mar 1, 2015
ABSTRACT The exponential growth of data traffic and connected devices, and the reduction of laten... more ABSTRACT The exponential growth of data traffic and connected devices, and the reduction of latency and costs, are considered major challenges for future mobile communication networks. The satisfaction of these challenges motivates revisiting the architecture of these networks. We propose an SDN-based design of a hierarchical architecture for the 5G packet core. In this article we focus on the design of its access cloud with the goal of providing low latency and scalable Ethernet-like support to terminals and MTC devices including mobility management. We examine and address its challenges in terms of network scalability and support for link-level mobility. We propose a link-level architecture that forwards frames from and to edge network elements (AP and routers) with a label that identifies the APs through which the terminal is reachable. An SDN local controller tracks and updates the users' location information at the edge network elements. Additionally, we propose to delegate in SDN local controllers the handling of non-scalable operations, such as broadcast and multicast messages, and network management procedures.
There is a growing interest in the standardisation of Multiple Input Multiple Output (MIMO) schem... more There is a growing interest in the standardisation of Multiple Input Multiple Output (MIMO) schemes for High Speed Downlink Packet Access (HSDPA) for future releases of UMTS. The I-METRA project, building on the legacy of METRA, has set up as one of its priorities to contribute to this standardisation effort by developing and evaluating pertinent transmission and reception schemes for this type of systems.
Olivier Bonaventure (Advisor)
This work was partially supported by a grant from FRIA (Fonds pour la formation
Polarization diversity in MIMO radio channels: experimental validation of a stochastic model and performance assessment
IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211), 2001
A stochastic MIMO radio channel considering (i) polarization diversity and (ii) unbalanced branch... more A stochastic MIMO radio channel considering (i) polarization diversity and (ii) unbalanced branch power ratio (BPR) is being validated by comparing Monte-Carlo simulations and experimental results using the eigenanalysis as benchmark. Based on results generated by the model, the influence of the BPR on the power gain of the parallel subchannels is presented.
This paper discusses the integration of open-source and proprietary software in the framework of ... more This paper discusses the integration of open-source and proprietary software in the framework of a European-funded pilot project. It simultaneously describes the topic of the project, the development of an integrated solution enabling to easily produce audiovisual content for Vocational Education and Training, the benefits the end-users enjoy thanks to the proposed solution, and the internal working procedures of the consortium, including the pros and cons of the selected groupware and the means to take users' opinions into account during an iterative prototyping process.
A link level MIMO radio channel simulator for evaluation of combined transmit/recieve diversity systems in frequency selective fading channels
Interaction of transmit diversity and proportional fair scheduling
The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring., 2003
In evolving 3G systems, the proportional fair packet scheduling algorithm promises an attractive ... more In evolving 3G systems, the proportional fair packet scheduling algorithm promises an attractive trade-off between average cell capacity and user fairness by exploiting multi-user selection diversity in time-shared channels. However, in these systems the option of antenna transmit diversity already exist, whose performance benefit is dependent on the considered scheduling strategy. This study focuses on the interaction between proportional fair
2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007
To adapt the transmission schemes in wireless communications, it is useful for the transmitter to... more To adapt the transmission schemes in wireless communications, it is useful for the transmitter to have actual knowledge of the channel's behavior. One way to build such knowledge is to predict the future state of the channel from past measurements. This paper presents two MIMO channel predictors, derived from existing SISO ESPRIT-based techniques. With a sampling rate of 4 samples per wavelength, 17 channel observations are sufficient to produce predictions over a few wavelengths in the case of a 4 x 4 MIMO system operating in a microcell environment. These predictors are quite simple and have limited computational needs.
2011 IEEE Vehicular Technology Conference (VTC Fall), 2011
This paper presents our sqTM burst mapping algorithm for downlink Mobile WiMAX systems. Based on ... more This paper presents our sqTM burst mapping algorithm for downlink Mobile WiMAX systems. Based on a treemap visualization algorithm, we introduce a new burst mapping scheme we called sqTM, greatly reducing the amount of wasted slots. We obtained between 60% and 75% reduction compared to some reference algorithms we implemented. These limited wastes are able to provide better cell throughput and larger cell capacities. Unfortunately, sqTM is significantly slower than reference algorithms, but still easily coping with 5 ms frames.
Link-level access cloud architecture design based on SDN for 5G networks
IEEE Network, 2015
ABSTRACT The exponential growth of data traffic and connected devices, and the reduction of laten... more ABSTRACT The exponential growth of data traffic and connected devices, and the reduction of latency and costs, are considered major challenges for future mobile communication networks. The satisfaction of these challenges motivates revisiting the architecture of these networks. We propose an SDN-based design of a hierarchical architecture for the 5G packet core. In this article we focus on the design of its access cloud with the goal of providing low latency and scalable Ethernet-like support to terminals and MTC devices including mobility management. We examine and address its challenges in terms of network scalability and support for link-level mobility. We propose a link-level architecture that forwards frames from and to edge network elements (AP and routers) with a label that identifies the APs through which the terminal is reachable. An SDN local controller tracks and updates the users' location information at the edge network elements. Additionally, we propose to delegate in SDN local controllers the handling of non-scalable operations, such as broadcast and multicast messages, and network management procedures.
2010 17th IEEE Symposium on Communications and Vehicular Technology in the Benelux (SCVT2010), 2010
To tackle an inherent security weakness of wireless environments, we propose the implementation o... more To tackle an inherent security weakness of wireless environments, we propose the implementation of a reputation procedure onto the routing protocol Ad-hoc On Demand Vector routing (AODV). This procedure relies on the overal cooperation of nodes taking part to the Wireless Mesh Network. Each node associates a reputation value to its neighbours, which reflects the trust it puts in them. Based on that reputation value, the hop count is increased or decreased, depending whether the intermediate node is trusted or not. This mechanism enables to select the most trustworthy paths in the mesh. We present preliminary experimental results obtained with our implementation.
ó A downlink space-time block coding transmission scheme is assessed via Monte Carlo simulations ... more ó A downlink space-time block coding transmission scheme is assessed via Monte Carlo simulations in a direct se- quence code division multiple access context. Raw symbol error rate performance of the space-time transmit diversity scheme de- ned in the UTRA/FDD standard serves as a benchmark. Exploit- ing space-time code properties, the new scheme facilitates radio channel equalization and space-time decoding
Smart Antennas IST Cluster Year 2000 Report
This report consists in the extended proceedings of the 1rst cluster meeting, held Oct 4 th in Ga... more This report consists in the extended proceedings of the 1rst cluster meeting, held Oct 4 th in Galway. It contains contributions of SATURN, METRA and ASILUM. The focus is on MIMO (Multiple Input Multiple Output) systems. The interest of MIMO w.r.t. radio link capacity is explained. Then principles of MIMO channel measurements are detailed. Eventually, the specific set-up of the
Offering streaming rate adaptation to common media players
2011 IEEE International Conference on Multimedia and Expo, 2011
This paper describes an adaptive streaming technique that exploits temporal concatenation of H.26... more This paper describes an adaptive streaming technique that exploits temporal concatenation of H.264/AVC video bitstreams and uses only standard RTCP reports as feedback mechanism. As a result, common media players like VLC, QuickTime or GStreamer based, can be used in a streaming session with improved viewing experience when accessing video content through bandwidth constrained connections. Further, an original probing technique
Implementation and Performance Evaluation of a P2PSIP Distributed Proxy/Registrar
The 2007 International Conference on Next Generation Mobile Applications, Services and Technologies (NGMAST 2007), 2007
Propagation Characterization and MIMO Channel Modeling for 3G
Signals and communication technology, 2004
Propagation Characterization and MIMO Channel Modeling for 3G Laurent Schumacher1, Lars T. Berger... more Propagation Characterization and MIMO Channel Modeling for 3G Laurent Schumacher1, Lars T. Berger2, Juan Ramiro-Moreno2 and Troels B. Serensen2 1 Computer Science Institute, Namur University, Belgium 2 ... The elements of H write fey witht'e [l... nRx] and; e [l... nTx]. ...
Multiple Antenna Processing and Performance in WCDMA
Signals and communication technology, 2004
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Papers by Laurent Schumacher