Agora: Open Market Architecture for Collaborative Mobile Internet
the Greek term for an open marketplace.
Agora is an open market architecture for collaborative
mobile Internet. In Agora people can be traders and/or customers - traders sell and customers buy wireless Internet
bandwidth. Motivation for Agora stems from an important fact that location
of mobile users tend to be clustered to form "people hot-spots"
for example, in shops, stations, buses and trains.
The main aim in Agora is to wirelessly exploit the unused capacity (e.g. bandwidth, service etc.) of
such user clusters.
The Agora Architecture combines several benefits:
An Open-market Architecture:-
Agora is an open market architecture where in-range mobile devices provide
mechanisms that allow users to harvest idle
devices to be used as personal network service providers, and obtain
necessary data services through them. The architecture offers a common
ground for integration of heterogeneous mobile terminals, networks,
services as well as applications.
Agora combines different ways of
exploiting distributed wireless diversity into a single architecture.
Users in Agora aggregate bandwidths by exploiting three different levels
of wireless diversity:
exploits wireless diversity by smartly striping packets across
different wireless links. Exploiting wireless diversity comes as an
benefit in the next generation mobile communication systems. Recent
research has experimentally demonstrated the benefits of exploiting
such wireless diversity to enhance reliability of the wireless
- Technology diversity --
this type of diversity combines the benefits of two wireless devices that are
operating using two different
communication technologies (e.g. GPRS and CDMA),
- Network diversity --
this is typically observed in a device with multiple interfaces that are attached
to the networks of different operators that observe uncorrelated data performance
on these interfaces,
- Channel diversity -- this combines benefits of
connecting to the same network (base station) but through different channel
Agora architecture allows incentive-based collaboration amoung in-range
mobile devices. The service discovery and charging scheme used in Agora provides
appropriate means of guiding the Agora system to its optimal operating point.
Devices in Agora that offer data forwarding services, recover their costs
associated with energy losses and traffic loading through credit arising
from using Agora's innovative charging scheme. The charging mechanism used in Agora is
fully centralized, where security is ensured.
A set of in-range mobile devices perform device/service discovery to leverage
service-level benefits of this architecture. Agora supports three types of
- Proxy-based Services:- that
involves forwarding data by other mobile devices,
- Local in-range services:- These are local yet collaborative services
for all the in-range devices. These include, for example, directory-based services,
distributed cache services etc.,
- Location-based services:- Here devices are able to locate each
other as well as reveal their own location information.
Full Application Support:- Agora integrates applications
with diverse QoS requirements such as:
For highly mobile environments, high bandwidth services is possible by
striping packets across multiple wireless links simultaneously. Striping
packets across number of such links has shown to significantly improve web
download and streaming performance by at least a factor of 2 and
- interactive web services and other e.g. ftp, mail etc.
- bandwidth-intensive streaming media and other multimedia services.
Fig. - The Agora Architecture for Collaborative Mobile Internet
Suman Banerjee (Dept. of Computer Sciences, University of
Wisconsin - Madison, USA)
Ian Pratt, Jon Crowcroft (Computer Systems Lab, University of Cambridge, UK)
Pablo Rodriguez (Microsoft Research, Cambridge, UK)
- MoB: A Mobile Bazaar for Wide-area Wireless Services.
Rajiv Chakravorty, Sulabh Agrawal, Suman Banerjee, Ian Pratt.
ACM Mobicom, 2005.
Transport Level Optimizations for Interactive Streaming Over Wide-area Wireless Networks
Julian Chesterfield, Rajiv Chakravorty, Suman Banerjee, Pablo Rodriguez, Ian Pratt, Jon Crowcroft.
ACM MONET Journal, June 2004.
Exploiting Diversity to
Enhance Multimedia Streaming Over Cellular Links.
Julian Chesterfield, Rajiv Chakravorty, Ian Pratt, Suman Banerjee, Pablo Rodriguez.
IEEE Infocom, Miami FL, 2005.
Performance Optimizations for Wireless Wide-area Networks:
Comparative Study and Experimental Evaluation
Rajiv Chakravorty, Suman Banerjee, Julian Chesterfield, Pablo Rodriguez, Ian Pratt.
ACM Mobicom, Philadelphia, PA, Sept 2004.
MAR: A Commuter Router Infrastructure for the Mobile Internet
Rajiv Chakravorty, Julian Chesterfield, Pablo Rodriguez, Ian Pratt, Suman Banerjee.
ACM Mobisys, Boston, June 2004