Publications

Enabling Asynchronous Awakenings in Wireless Sensor Networks Towards Removing Duty-Cycle Barriers

Authors: Giannis Kazdaridis, Panagiotis Skrimponis, Ioannis Zographopoulos, Polychronis Symeonidis, Thanasis Korakis and Leandros Tassiulas

Conference:  ACM WinTech 2017, ACM Mobicom 2017, Snowbird, Utah, USA, 20 October 2017

Abstract: Typical wireless sensor network applications follow duty-cycle mechanisms, yielding important energy savings by reducing the power consumption of idle listening. However, this approach still dictates predefined cycles of active operation, which in some application scenarios is meaningless. Extended lifetime can be achieved by asynchronously awakening sensor network's nodes only when truly required. In this work we present NITOS wake-up receiver that can be employed by typical sensor nodes to provide asynchronous wake-ups and substantially reduce their energy expenditure. Our wake-up circuit operates in the 868 MHz band and is activated by LoRa frames using OOK modulation. The developed system supports selective awakenings with the aid of a low-power micro-controller dedicated to sample the acquired signal and identify the wake-up address.

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GENI in the Classroom

Authors: Vickraj Thomas, Niky Riga, Sarah Edwards, Fraida Fund and Thanasis Korakis

Publication Details: GENI Book, pp 433-449, Springer, 2016

Abstract: One of the great successes of GENI has been its use as a remote laboratory by instructors of networking, distributed systems and cloud computing classes. It allows instructors to provide hands-on learning experiences on a real, large-scale network. Reasons for this success include GENI’s ease of use, access to resources such as programmable switches and wireless base stations that are not ordinarily available at most schools, support for collaborative experimentation and ease of recovering from mistakes. The GENI community has created and made available to instructors ready-to-use exercises based on popular networking textbooks. These exercises cover a range of topics from basic networking to advanced concepts such as software defined networking and network function virtualization. They include wired and wireless networking based exercises. GENI is also used as a platform for applications that enhance STEM education at the high-school level and as a platform for MOOC courses that use an interactive approach to teach Internet concepts to non-computer scientists.

Download paper: Geni in the Classroom

SDN Implementation of Slicing and Fast Failover in 5G Transport Networks

Authors: Dimitris Giatsios, Kostas Choumas, Paris Flegkas, Thanasis Korakis and Daniel Camps-Mur

Conference: EuCNC 2017, Oulu, Finland, June 2017

Abstract: Software-defined networking is at the root of future 5G transport network design. Among others, it allows for automated network reconfiguration and network slicing support. In this paper we present an OpenFlow-based implementation of a control plane area in the transport network architecture envisioned by the 5G-XHaul project. We analyze the implementation of the slicing mechanism at the network edge. Furthermore, we propose a simple low-overhead fast proactive failover scheme for recovering from single link failures, without the delays and packet drops associated with reaching a remote controller entity.

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Video aware Multicast Opportunistic Routing over 802.11 two-hop mesh networks

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

Journal: IEEE Transactions on Vehicular Technology, February 2017

Abstract: Opportunistic routing benefits from the broadcast nature of the wireless communication and outperforms the packets losses happen in a wireless environment, especially in case of multicast. In this work, we present and evaluate the performance of an innovative video-aware multicast opportunistic routing algorithm in 802.11 two-hop mesh networks. We enhance a state-of-the-art opportunistic routing scheme, namely MORE, that offers multicast but is not efficiently applicable to video streaming applications. Our scheme is able to support real-time applications with time-constraints. We improve the received video quality by classifying/prioritising the video traffic and efficiently orchestrating the multiple transmitters involved in multicast routing. The presented scheme, namely ViMOR, is evaluated through extended experimentation in the wireless testbed of NITOS. ViMOR succeeds in increasing the perceived video quality by up to 270% in a few scenarios or up to 175% in average, compared to MORE.

Download paper: tvt_2017_vimor_journal.pdf

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