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Marketplaces as Communication Patterns in mobile ad-hoc Networks*
Daniel Görgen, Hannes Frey, Johannes K. Lehnert and Peter Sturm
System Software and Distributed Systems Research Group
University of Trier
* This work is funded in part by DFG, Schwerpunktprogramm SPP1140 “Basissoftware für selbstorganisierende Infrastrukturen für vernetzte mobile Systeme”
Mobile multihop ad-hoc Networks Mobile devices
Wireless communication facility Positioning
Large scalead-hoc networks University campus,
downtown area
Communication mainlyover many hops
High mobility Frequent topology changes Network partitions Permanent link failure
Communication Model Altruistic Demand and supply
Find a match Make an agreement Possible matches are unknown
Applications with low time constraints Digital ride boards, auction systems, …
Trivial but impractical solutions Flooding the entire network
High network load Network partitions
Awaiting a matching counterpart In direct transmission range Low probability
The marketplace solution
Fixed geographic regions High device density Known position
Devices at market acting on behalf of a user
Geographic routing of agents/data To and from marketplaces
Negotiation at a marketplace Geographic limited broadcast Topology-based Routing
Definition of home zones Negotiation results are sent
back to a defined home zone
R
OO
O
R
R
O
R
Request
Offer
R
R R
O
O
O
Message Routing To and from marketplaces Geographic routing
e.g. greedy algorithm Additional: course information
Messages can be carried over network partitions
Message duplication to avoid message losses Sender keeps messages until
reception is acknowledged Duplicated messages can be
detected on the marketplace
Losses are still possible Device crash
S
D
Communication at Marketplaces
More reliable communication High device density Network partitions are rare Message loss can be detected
Agents stay longer at market
Discovery Broadcast only in a small region
Discard messages outside Flooding or neighbor knowledge broadcasts
Negotiation Topology-based routing Broadcasts as above
Only simple solutions are implemented yet
UbiBay – A mobile auction system
Auction at marketplaces Low value goods Direct neighborhood
Agents Auction agent
Controls the auction Discovery agent
Lists all auctions at marketplace Bid agent
Bids on behalf of a user
15
10
Further Aspects Caretaker agents
Load Monitoring Splitting/Joining of
marketplaces Duplicate detection
Primary at marketplaces
Caching of information/data Public bill-board
Collecting information about device accumulation Hotspot detection enhanced position-based
routing
Electronic Rideboard
Lift offers and demands at marketplaces Localized service Non time-critical Simple agreement protocol
Splitting marketplaces Classify agents by
destinations postal code 01099…54290 on market A 54291…99998 on market B
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12
9
4
568
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0
01099-9999801099-54290
54291-99998
Evaluation
Own Simulation environment Mobile MANETs
Up to 10 000 devices Up to 10 km x 10 km
High abstraction level Visualization One implementation for both
simulation and real hardware
Mobility Models Exhibition, festival and campus
Status and further work
Prototype implemented Simulation and real-life
Already implemented Applications Electronic ride board UbiBay - auction system
Additional service agents Improved Message routing
Position based Marketplace communication
Integration in SOUL-Project Self-organized ubiquitous
learning
Preparation for field trials First tests with WLAN, GPS,
PDAs and notebooks
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