Alaeddine EL-FAWAL. Thesis director : Jean-Yves Le Boudec. Data Dissemination for Spot Applications in Ad-Hoc Networks. Private Defense, 3 April 2009, EPFL. Overview on the PhD Work. Supported by 2 projects: Haggle: European project in Situated and Autonomic Communications
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Thesis director :
Jean-Yves Le Boudec
Data Dissemination for Spot Applications in Ad-Hoc Networks
Private Defense, 3 April 2009, EPFL
Dealing with different facets of uncoordinatedad-hoc wireless
networks and deals with challenges at all networking layers
Dramatic expansion of WIFI interfaces: laptops, PDAs, mobile phones, video games and even with peripherals and vehicles.
(number of nodes that receive a packet).
Source / Relay
Source / Relay
Source / Relay
Source / Relay
An autonomic mechanism for data dissemination that adapts to
this diversity in scenarios is a must, otherwise
Data dissemination through limited epidemic forwarding :
SLEF is designed to hold in all scenarios, in particular
in very dense and very sparse ones
SLEF implements 6 essential functions needed for a sustainable service
1. Congestion control: first mechanism proposed for broadcast in ad hoc networks
Scheduler / fairness: A scheduler is needed to decide which packet to serve. It is based on Source ID to ensure some level of fairness.
4. Spread control (adaptive TTL)
5. Forwarding factor control
6. Buffer management
Trade-Off Spread vs. Application Rate
Spread: number of nodes that receive a packet.
With fixed TTL
TTL limit= 2
N : Spread
FF: Forwarding Factor
R0: Nominal Rate of MAC Layer
λ : Application Rate
Real time Age
Send/receive the same pkt
Age = Age +K0
receive any pkt
Age = Age + K1
by time: 8h -> 255
Age > 255
Adjusting the spread-rate balance according to the application needs
Default values for K0 and K1 are computed in the thesis
One send/receive event
Two send/receive events:
The green nodes are inhibited:smaller forwarding factor
Transmission would be redundant
Why:To Minimize redundancy (save resources)
Virtual Rate: The max rate a packet is transmitted with
For each send / receive event on a given pkt:
1- The virtual rate is computed as follows:
R0 : nominal MAC rate [pkts/s]
RcvCount : number of times the pkt is received
SendCount : number of times the pkt is sent
aandb : are coefficient less than 1: a=0.1, b=0.01
3- The pkt is allowed to be transmitted only after: current time +
(similar to a back-off system)
Unlike other mechanisms, the virtual rate based forwarding factor control allows transmitting the pkt multiple times if needed.
2- vRate decreases exponentially with send/receive events.
The smaller the vRate is, the longer the back-off time is:
The pkt might be dropped before being transmitted
Lived the highest number of send/receive events
Network Simulator: JIST-SWANS, A JAVA simulator for Ad Hoc networks
Vehicular Mobility Simulator: STRAW, an extension of JIST-SWANS. It provides a mobility model based on the operation of the real vehicular traffic.
Topo : 2-lanes road, speed limit 80Km/h
MAC : 802.11/b
Channel : Fading
K0 = 25
K1 = 0.1
Range : 300 m in average
Density: 12 vehicles/Km
Very dense (Traffic jam)
Very dense (Traffic jam): +200 neighbors
Idea: implement a mutual exclusion mechanism for broadcast in order to avoid collision
SLEF is practical and performs well on very resource-limited devices
Performance evaluation of SLEF through measurements
Nodes are distributed over 12 buildings in EPFL
We propose SLEF: data dissemination middleware for spot applications
Prototyping SLEF for 4 platforms
Building a testbed for wireless networks protocols
SLEF performs better than fixed-TTL:
Performance evaluation of SLEF:
Collaboration with LCA3: Prof. Patrick Thiran and Adel Aziz
Cross-Layer Optimization for UWB IR Networks (MICS)
Data Dissemination for Spot Applications (Haggle)
Problem: Conventional detection method
Solution: Power independent detection method.
10 users, LOS Indoor Office Channel model by IEEE P802.15.4a
Total Error: Et=PMD + PFA
Proba of Misdetection: PMD
Scenario: Persistent broadcast in presence of intermittent connectivity
El Fawal, Alaeddine ; Le Boudec, Jean-Yves: A Robust Signal Detection Method for Ultra Wide Band (UWB) Networks with Uncontrolled Interference. In: IEEE Transactions on Microwave Theory and Techniques (MTT,) 2006.
El Fawal, Alaeddine ; Le Boudec, Jean-Yves et al. Tradeoff Analysis of PHY-aware MAC in Low-Rate, Low-Power UWB networks.In: IEEE Communications Magazine, vol. 43, num. 12, 2005, p. 147.
Raya, Maxim ; Aad, Imad ; Hubaux, Jean-Pierre ; El Fawal, AlaeddineDOMINO: Detecting MAC layer greedy behavior in IEEE 802.11 hotspots. In: IEEE Transactions on Mobile Computing, December 2006
El Fawal, Alaeddine ; Le Boudec, Jean-Yves ; Salamatian, KaveMulti-hop Broadcast from Theory to Reality: Practical Design for Ad Hoc Networks. In: First International Conference on Autonomic Computing and Communication Systems, October 2007.
El Fawal, Alaeddine ; Le Boudec, Jean-Yves ; Salamatian, KaveVulnerabilities in Epidemic ForwardingIn: The First IEEE WoWMoM Workshop on Autonomic and Opportunistic Communications (AOC2007), 2007
Merz, Ruben ; El Fawal, Alaeddine ; Le Boudec, Jean-Yves ; Radunovic, Bozidar et al. The Optimal MAC Layer for Low-Power UWB is Non-Coordinated.In: IEEE International Symposium on Circuits and Systems (ISCAS 2006), 2006
El Fawal, Alaeddine ; Le Boudec, Jean-YvesA Power Independent Detection Method for UltraWide Band (UWB) Impulse Radio Networks. In: IEEE International Conference on Ultra-Wideband (ICU 2005), 2005
El Fawal, Alaeddine ; Le Boudec, Jean-Yves
Synchronizing Method for Impulse Radio Networks, Date: 2005
El Fawal, Alaeddine ; Salamatian, Kave et al. A framework for network coding in challenged wireless network. Presented at: MobiSys 2006, Uppsala - Sweden, June 19-22, 2006.
MERCI DE VOTRE ATTENTION
Wireless router: ASUS WL-500GP
Technical specifications: 8MB Flash, 32MB RAM, 266MHz, 2 USB 2.0 ports
Configurable wireless interface: using Atheros card with MadWIFI driver (setting RTS/CTS Th, Tx power, Tx queue length…).
Mobility: using plumb batteries, +4 hrs lifetime with full power transmission at full rate