Research on Wireless Networks at NKUA Prof. Ioannis Stavrakakis Communication Networks Laboratory Dep. of Informatics and Telecommunications National &

Research on Wireless Networks at NKUA

Prof. Ioannis Stavrakakis Communication Networks Laboratory

Dep. of Informatics and TelecommunicationsNational & Kapodistrian University of Athens (NKUA)

Leonidas TzevelekasDagstuhl Seminar, March 2004

Leonidas TzevelekasDagstuhl seminar, March 2004

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Outline

Scalability of Ad hoc Routing Protocols, C. Santivanez, I. Stavrakakis

On multi-hop extensions of WLANs,A. Panagakis, E. Balafoutis, I. Stavrakakis

IST Broadway Project,A. Vaios, I. Stavrakakis

Wireless Sensor Networks, L. Tzevelekas, I. Stavrakakis


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Scalability of ad hoc routing protocols

Work’s objectives:1. To define and measure scalability in ad hoc

networks

2. To examine existing routing protocols for ad hoc networks with respect to scalability

3. To propose new, ‘better’ (more scalable) routing protocols for ad hoc networks


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Definitions of Scalability Network’s scalability (quantitatively, qualitatively)

Routing protocol’s scalability (quantitatively, qualitatively)

Examples Network Scalability Factor:

Routing protocol Scalability Factor:

Scalability of ad hoc routing protocols

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Scalability of ad hoc routing protocols Family of Fuzzy Sighted Link State algorithms

(FSLS Algorithms)Protocol Characteristics the frequency of Link State Updates (LSUs) propagated to

distant nodes is reduced a node transmits a Link State Update (LSU)

only at particular time instants the Time To Live (TTL) field of the LSU is set to a value

that is a function of the current time Hazy Sighted Link State (HSLS)

latency versus distance curve: optimal performance when linear

optimal balance between proactive and sub optimal routing overhead


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Scalability of ad hoc routing protocolsRelated Publications

C. Santivanez, B McDonald, I. Stavrakakis, Ram Ramanathan, “On the Scalability of Ad Hoc Routing Protocols. Part II: Asymptotic Analysis with Respect to Traffic”, IEEE/ACM Transactions on Networking [About to be submitted or submitted]

C. Santivanez, Ram Ramanathan, I. Stavrakakis, B McDonald, “On the Scalability of Ad Hoc Routing Protocols. Part I: Making Link State Routing Scale”, IEEE/ACM Transactions on Networking [ submitted]

C. Santivanez, B McDonald, I. Stavrakakis, Ram Ramanathan, “On the Scalability of Ad Hoc Routing Protocols”, IEEE INFOCOM 02, N. York, USA

C. Santivanez, Ram Ramanathan, I. Stavrakakis, “Making Link-State Routing Scale for Ad Hoc Networks”, MobiHoc 2001, Oct. 4-5, 2001, Long Beach, CA, USA


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The main problem: Need for higher capacity/user

Motivation : to support high-rate apps to allow for direct communication between MTs to support Hotspots requiring higher capacity

“In-fashion” solution: Ad hoc in WLANs? Via a Multi-hop Cellular Network (MCN)

On multi-hop extensions of WLANs


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On multi-hop extensions of WLANsEvaluation of MCN (simulation environment) ns simulator (version 2.1b7) MAC : IEEE 802.11 DCF mode Propagation model: two ray path loss model Routing: DSR Transport protocol: UDP packet size: 512 bytes default parameters of the simulator (WaveLan Card)

(except transmission range, range of interference)


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AP

On multi-hop extensions of WLANs The performance of an MCN is rather poor

(in terms of throughput, for inter-cell traffic)

Doughnuts “taste” better than cookies (as expected: spatial reuse up to the edge, lower max hop count)

“Taste” of Doughnut depends on: Interference Dimensions of Doughnut

Additional “taste” comes at the cost of increased power consumption (in case where last hop longer)


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Related Publications Antonis Panagakis, Elias Balafoutis and Ioannis Stavrakakis,

“Study of the capacity of multi-hop cellular networks”, QofIS 2003, 1-3 October 2003, Stockholm, Sweden

Athanasios Vaios, Konstantinos Oikonomou and Ioannis Stavrakakis, "A Centralized Routing Scheme Supporting Ad Hoc Networking in Dual Mode HIPERLAN/2 System", IST Mobile Summit 2003, 15-18 June, Aveiro, Portugal

On multi-hop extensions of WLANs


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IST Broadway Project

IST-Broadway:IST-Broadway: “the way to broadband access at 60GHz”

Duration: 01/01/2002 – 31/12/2004

PARTNERS:1. CRM, Motorola Labs Paris2. Intracom3. National and Kapodistrian University of Athens4. TNO Physics and Electronics Laboratory5. Farran6. Technische Universität Dresden7. Institut für Mobil und Satellitenfunktechnik - IMST


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Motivation Standard ETSI BRAN HiperLAN/2 features 5.2 GHz AP is the bottleneck when the number of users demanding very

high bit-rates is increased All the connections have to pass through the AP even when

MTs are very close peer-to-peer communications are penalized

Objective: Offload the 5 GHz mode of operation Based on HiperLAN/2: Enhanced HiperLAN/2 System with two

modes of operation Mode 1: Standard HiperLAN/2 Mode 2: HiperLAN/2-like operation at 60 GHz


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IST Broadway Project Basic Principle: the 5 GHz mode is considered as

the default and signalling mode

When connectivity exists the AP manages the switching between different modes for all MTs

Two types of equipment For the AP: operates at both frequency-bands

simultaneously For the MTs: operate either at 5 GHz or 60 GHz (requiring a

switching between the two bands)


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Centralized Ad hoc Network Architecture Centralized Ad hoc Network Architecture (CANA)(CANA)

AP Access Point

CH Cluster Head

FN Forwarding Node

Mobile Terminal

5 GHz Range

60 GHz Range

5 GHz Data Flow

60 GHz Data Flow

AP

CHCH

FNCH

CHCH

CH

FNFN

CH


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IST Broadway

Related Publications K. Oikonomou and I. Stavrakakis, “Analysis of a Probabilistic

Topology-Unaware TDMA MAC Policy for Ad Hoc Networks”, IEEE JSAC Special Issue on Quality of Service Delivery in Variable Topology Networks

K. Oikonomou, A. Vaios, S. Simoens, P. Pellati and I. Stavrakakis, “Centralized Ad-hoc Network Architecture (CANA) Based on an Enhanced HiperLAN/2 System”, PIMRC 2003, 7-10 September, Beijing, China

K Oikonomou and I. Stavrakakis, “Throughput Analysis of a Probabilistic Topology-Unaware TDMA MAC Policy for Ad Hoc Networks”, QofIS, 1-3 October 2003, Stockholm, Sweden


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Wireless Sensor Networks

Related Project: E-NEXTE-NEXT Network of Excellence in emerging network

technologies IST FP6 programme Duration: 2004 – 2005 Task Forces:

1. TF1 – scalable routing 2. TF2 – distributed router architecture to gain

scalability3. TF3 – traffic driven scalabilit4. TF4 – new task force on sensor networks

proposed by us


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Wireless Sensor Networks

My personal interests

1. Power aware / energy efficient routing for WSNs

2. Design of cross-layer algorithms for improved power efficiency

3. Real-life deployment of test networks

Questions

1. Direction of WSN related research

2. Impact of this technology on future generations

3. Trends & Hype: Where is the border?


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More Information

Our web addresses

http://cnl.di.uoa.gr – Communication Networks Lab

http://cgi.di.uoa.gr/~istavrak – Prof. I. Stavrakakis web page

http://users.cnl.di.uoa.gr/~ltzev – Personal Web Page

Documents

Research on Wireless Networks at NKUA Prof. Ioannis Stavrakakis Communication Networks Laboratory Dep. of Informatics and Telecommunications National &