Wire Communications Laboratory

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University: University of Patras
Name of sponsoring Professor: Assistant Professor Spyros Denazis
Department: Department of Electrical & Computer Engineering
Laboratory: Wire Communications Laboratory

P2P Research Group

Our group is working in p2p architecture and it focuses in three wide research areas. The first is the distributed optimization of p2p systems and so their distributed and dynamic resource management with respect to the performance of applications that use them. The second is the creation of architectures for the development self-organized p2p databases use of them in order to develop distributed query mechanisms. At last p2p live streaming and p2p video on demand are the application domains where we apply our proposed systems.

Research:

1. Enabling locality in a balanced P2P overlay

In this work a DHT architecture is being presented that exploits network locality and simultaneously offers a framework for balancing the data stored in the overlay without constraint this process from the requirements of the routing functionality of the DHT.

Authored Papers:

• Enabling locality in a balanced peer to peer overlay, N. Efthymiopoulos, A. Christakidis, S. Denazis, O. Koufopavlou, IEEE Globecom 2006,World Class Solutions - Networking the Globe Symposium, Nov. 2006

2. Locality aware structured overlay for P2P live streaming

In this work we present the algorithms that we developed in order to create a locality aware structured graph through the use of distributed optimization. We also briefly present the performance of our overlay in P2P live streaming.

Authored Papers:

• L-CAN: Locality aware structured overlay for P2P live streaming, N. Efthymiopoulos, A. Christakidis, S. Denazis, O. Koufopavlou, 11th IFIP/IEEE International Conference on Management of Multimedia and Mobile Networks and Services 2008.

University: University of Patras
Name of sponsoring Professor: Associate Professor Michael Logothetis
Department: Department of Electrical & Computer Engineering
Laboratory: Wire Communications Laboratory

Research:

Wireless LAN Simulation

Using Opnet modeler, we have made simulations of scenarios employing wireless LANs (WLANs) under the 802.11 – 802.11e protocols, studying the performance of the WLAN.

Authored Papers:

• I. Papapanagiotou, J. S. Vardakas, M.D. Logothetis and S.A. Kotsopoulos, “Performance Evaluation of IEEE 802.11e based on ON-OFF Traffic Model”, in Proc. of the 3rd International Mobile, Multimedia Communications Conference, Mobimedia 2007, Nafpaktos, Greece, 27-29 August 2007.
• J. S. Vardakas, M. K. Sidiropoulos and M. D. Logothetis, "Performance Behavior of IEEE 802.11 Distributed Coordination Function", IET Circuits, Devices & Systems, Vol. 2, No. 1, pp. 50-59, February 2008.

Teaching

Lab exercises for the course Computer Communication Networks:

1. Simulation of waiting systems

• Introduction to OPNET modeler
• Simulation of the M/M/1/? waiting system
• Simulation of the M/M/1/m waiting system

2. Simulation of the Ethernet protocol

• Description of the Ethernet protocol
• Simulation of an Ethernet network

3. Simulation of multiple access protocols

• Simulation of the Aloha protocol
• Simulation of the CSMA protocol
• Simulation of the CSMA/CD protocol

4. Simulation of the IEEE 802.11 protocol:

• Description of the IEEE 802.11 protocol
• Analytical model for the calculation of the saturated throughput of the wireless LAN, using a programming language
• Simulation of the IEEE 802.11 protocol
• Evaluation of the presented analytical model through the comparison of analytical and simulation results

5. Simulation of packet-switched networks

• Simulation of a packet-switched network, in order to find the end-to-end delay of a packet

Research:

1. IP Multimedia Subsystem (IMS) architecture simulation and implementation of Multimedia Services.

2. Quality of Services (QoS) and applications on Next Generation Networks.

This simulator will be used for the diploma theses of the 5th-year under-graduate students and for further investigation regarding NGN networks.

University: University of Patras
Name of sponsoring Professor: Stavros A. Kotsopoulos
Department:Department of Electrical & Computer Engineering

Laboratory: Wireless Telecommunication Laboratory

Research:

1. Wireless LAN Simulation:

IP Telephony is a driving force for research and investments in the Internet and Network applications. With the advent of WMAN 802.16, the wireless VoIP is expected to be the hot application embedded in every wireless handheld. Along with the Broadband Access, local access is expected to play an important role. Using OPNET Modeler, we are currently making simulation of scenarios employing WLANs, WMANs and VoIP calls, studying the behaviour and the weaknesses of the system.

Authored papers :

• A new MAC protocol for supporting Quality of Service in 802.11 Wireless LANs, G. S. Paschos, I. Papapanagiotou, S. A. Kotsopoulos, G. Karagiannidis, EURASIP Journal on Wireless Communications and Networking, Volume 2006, Article ID 65836

• A Heuristic strategy for IEEE 802.16 WiMAX scheduler for Quality of Service, G. S. Paschos, I. Papapanagiotou, C.G. Argyropoulos, S.A. Kotsopoulos, 45th Congress FITCE 2006, 30 August - 2 September 2006, Athens, Greece.

2. Ad Hoc Networking Simulation:

Ad Hoc Networking is a key topic for Wireless Communications. The wireless computers are able to communicate without the need of any infrastructure at all. We use OPNET Modeler to simulate Ad hoc Routing Protocols, MAC Layer Enhancements and Quality of Service behaviour.

Authored papers:

• Performance analysis of a new Admission Control for 802.11 WLAN Networks in ad hoc mode, G. S. Paschos, I. Papapanagiotou, E.D. Vagenas, S.A. Kotsopoulos, CSNDSP 2006, 19-21 July, Patras.

3. Wireless Sensor Networks:

Sensor Networks is an amazing application of wireless Networks. Small, low-cost and easy to build nodes are deployed in an area able to sense activities and report through ad hoc communications. Using OPNET Modeler, we simulate Sensor Localization and Power Management.

University: University of Patras, Greece
Name of sponsoring Professor: Prof. Dr. Stavros Koubias (koubias@ece.upatras.gr)
Department: Department of Electrical & Computer Engineering (www.ece.upatras.gr)

Research Group: Applied Electronics Laboratory (APEL) (www.apel.ee.upatras.gr)

Research:

Routing and MAC layer in Wired and Wireless Networks

The OPNET simulator is be used for research purposes in the Applied Electronics Laboratory, Dept. of Electrical & Computer Engineering, University of Patras. More specifically, this simulator is be used mainly by post-graduate students working on their PhD theses. The main fields of this research work belong in the following categories:

• Distributed Real-Time Networking Systems

• Industrial Fieldbuses

• Wireless High-Performance Real-Time Networks

• Sensor Networks

• Hybrid (Wired/Wireless) Networking Structures

• Interworking Structures for High-Speed Networks

In addition this simulator will be used for the diploma theses of the 5th-year under-graduate students for the course of "Distributed Embedded Real-Time Systems", which is equivalent of a Master thesis. Until know the following diploma thesis have been completed:

• Study and development of self-organized wireless sensor networks.

Authored Papers:

22/9/2004 - WFCS 2004 : A Hybrid Adaptive Routing Protocol for Ad Hoc Wireless Networks (pdf)

19/9/2005 - ETFA 2005 : ZRP versus DSR and TORA-A comprehensive survey on ZRP performance(pdf)

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