Publications

Towards the efficient performance of LTE-A systems: Implementing a Cell Planning framework based on Cognitive Sensing

Authors: Virgilios Passas, Nikos Makris, Stratos Keranidis, Thanasis Korakis, Leandros Tassiulas

Conference:  IEEE International Workshop on Cognitive Cellular Systems, Rhine River, Germany, September 2-4 2014

Abstract: LTE and LTE-A have dominated as a 4G enabler protocol, adopted by the majority of the network providers worldwide. The efficient performance of an LTE network relies on the selected frequency within an operating band that the cell operates, by taking into account all the potential factors that can affect it. Since cognitive radio is targeting towards the maximization of spectrum utilization, it is crucial that it is adopted in the spectrum allocation process. In this work, we propose an efficient scheme for cell planning by employing spectrum sensing techniques. By exploiting spectral information collected by several sensing devices, we appropriately select the center frequency inside the operating band, towards maximizing the quality of the end user experience. Our algorithms are implemented for the downlink channel, considering a variety of configurations and topologies. Finally, our implemented mechanism is evaluated in the real world deployment of the NITOS Future Internet facility, using commercial LTE enabled femto cells and UEs, while USRP sensing devices are employed for high quality spectral information provisioning.

Download paper: Passas_LTECellPlanning_IEEECCS_2014.pdf

Building an infrastructure for experimentation between Brazil and Europe to enhance research collaboration in future Internet

Authors: Iara Machado, Leandro Ciuffo, Daniel Marques, Tiago Salmito, Michael Stanton, Antonio Abelem, Jose Rezende, Marcos Salvador, Sebastia Sallent, Leonardo Bergesio, Serge Fdida, Mayur Channegowda, Leandros Tassiulas and Dimitris Giatsios

Conference: TERENA Networking Conference, Dublin, Ireland, April 2014

Abstract: This paper describes the experience of RNP, the Brazilian research and education network, in creating a large-scale research facility for experimentation on Future Internet as a member of the FIBRE (Future Internet testbeds experimentation between BRazil and Europe) project. Its main goal is to create common space between Brazil and EU for Future Internet experimental research into network infrastructure and distributed applications, by building and operating a federated EU-Brazil Future Internet experimental facility. The FIBRE testbed is currently composed by a federation of 13 local testbeds (a.k.a. experimental islands), located in different R&E organizations. The FIBRE infrastructure combines heterogeneous physical resources and different technologies, including OpenFlow, wireless and optical communications. We also present the architecture of FIBRE, which allows users to access the testbed through an integrated interface for either experimental or control planes, and provides a common access to the different underlying Control and Monitoring Frameworks (CMFs) for Future Internet experimentation.

Download paper: tnc2014_paper_TNC2014FIBREFullpaper.pdf

NITOS Mobile Monitoring Solution: Realistic Energy Consumption Profiling of Mobile Devices

Authors: Stratos Keranidis, Giannis Kazdaridis, Virgilios Passas, Giannis Igoumenos, Thanasis Korakis, Iordanis Koutsopoulos, Leandros Tassiulas

Conference:  ACM e-Energy 2014, Oxford, UK, June 11-13 2014

Abstract: The unprecedented penetration of "smart'' mobile devices in everyday use case scenarios, along with their energy greedy profile have motivated researchers in the field of wireless networking, towards reducing energy consumption wherever possible. In order to support the design of energy efficient protocols, in-depth energy consumption profiling of mobile devices needs to be applied, through long term monitoring and under realistic conditions. To this aim, we have developed a tiny device able to fit in the battery pack of smartphones and monitor the resulting power consumption in an on-line way. In this work, we detail the components of the developed framework and demonstrate two indicative scenarios that showcase how the diversity of experimental conditions and configurations can significantly impact energy consumption.

Download paper: Keranidis_NITOS_MMS_e-Energy_2014.pdf

Video-aware Multicast Opportunistic Routing over 802.11 mesh networks

Authors: Kostas Choumas, Ilias Syrigos, Thanasis Korakis and Leandros Tassiulas

Conference:  SECON 2014, Singapore, Singapore, 30 June - 3 July 2014

Abstract: In this paper, we propose and characterize the performance of a novel video-aware Opportunistic Routing (OR) algorithm for multicast, using a one-hop and two-hop forwarding scheme in 802.11 mesh networks. We believe that the OR approach exploits the inherent broadcast nature of the wireless medium and adapts very well in the lossy wireless environment. Inferring from the above, we extend a state of the art routing algorithm, namely MORE, that leverages on this approach and offers multicast support, but is not efficiently applicable in video streaming. By employing our scheme, we enable support for video streaming application with hard time-constraints. In addition, we focus on the orchestration of the packet transmissions and the prioritization of the video traffic towards improving the video-perception quality of the end users. In order to evaluate the proposed scheme, we conducted experiments in a realistic medium-scale wireless testbed. Our results show that the proposed scheme increases the average video-perception quality, measured in PSNR, by up to 270% in some cases or up to 175% in average, compared to the MORE algorithm.

Download paper: kohoumas_secon_2014_vimor.pdf

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  1. Experimental Evaluation and Comparative Study on Energy Efficiency of the Evolving IEEE 802.11 Standards
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