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

1

12

9

4

568

3

4

5

6

7

7

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