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NATACHA EU project
- Description of research project
NATACHA is
a project funded by the European Commission's GROWTH programme. It started
on May 1st, 2002
and will terminate July 31st,
2004. The NATACHA project will provide a new generation mobile
real-time internet connection up to the aircraft through a bi-directional
high bandwidth satellite communication link. NATACHA focuses on the
airborne systems part of the communication system and its interface
to the satellite link.
The objectives of the NATACHA project are summarised as follows:
- to
derive requirements for the communication system from current and
future airborne information services.
- to implement
multimedia internet technology for real-time information transfer
between air and ground anywhere and between on-board systems.
- to develop
an organisation of a unified on-board data communication as an IP
based network with routers and servers, as an extension of the ground
based internet and the services it provides : for a work environment
extension in a mobile computing environment "Office in the sky concept"
- enabling continued productivity of professional travellers and to
enhance productivity of the aircraft crew in cockpit and cabin. NATACHA
stands for an extension of the public consumer environment by enabling
real-time access to public internet services on-board of aircraft.
- to
evaluate the airborne internet with example application services from
every domain
The
project is focussed on critical technologies which are required to enable
the private and professional public community to access a new generation
of mobile internet services. The key technologies are the airborne part
of the communication system with the interface to the satellite link.
The functional applications in the flight crew, cabin crew and passenger
domain themselves are not the prime subject of the project. The applications
are studied as examples to establish communication system requirements
and constraints and to evaluate function and performance of the communication
system on the test bed.
- Role of the University of
Rome in NATACHA Project
UoR is involved in the study
phase in which an analysis of broadband satellite communication standards
(DVB and S-UMTS) will be performed in order to define the NATACHA system
architecture.
In the framework of the project
UoR will develop a Bandwidth on Demand protocol to provide users with
multimedia contents. In such a study UoR will design also a Data Link
layer suited for the satellite link communication within the Broadband
Communication Equipment. Radio Resource Management and its related
issues will be studied and deeply investigated.
- Ongoing Researches, Results and Papers
The aim of Natacha project
is to provide passengers with broadband services up to aircrafts. To
achieve this scope we studied with OPNET the main aspect of Radio Resource
Management. A Power Assignment algorithm, more than one Admission Control
and Packet Scheduling policies have been implemented.
The Power Assignment algorithm
focused on minimizing inter airbones interference, maintaining
QoS connections over a prefixed threshold. On the admission connection
side three different Admission Control Algorithm are implemented: a
traffic load based and two effective bandwidth based techniques. The
load based technique estimates traffic and it accepts a new connection
only if the network load, considering also the new connection, is under
a prefixed threshold. The other algorithms estimate the effective bandwidth
of each connection and accept or discard a new connection if the whole
radio resources needed for serve all the users exceed or not system
capacity. Packet Scheduling algorithms
decide the way to assign bandwidth to each connection. The two approaches
considered are based on two different policies:the Earliest Deadline
First (EDF) and the Packet by Packet Generalised Processor Sharing (PGPS).
The former try to satisfy in a frame the connection needs, the latter
shares radio resource more fairly among the standing up connections.
The bandwidth assignment algorithms implemented differ on the number
of channels assigned to each connection accepted by the system: one
channel to each connection in the first one and up to six in the second
one.
In
order to test results of adopting different solutions, i.e. different
algorithms of Scheduling and Admission Control, the OPNET simulation
tool have been used. Statistics collected are:
- Blocking Probability;
- End-to-end transmission delay;
- System Throughput;
- Packet loss;
- System Interference.
By
mean of OPNET, the developed modules are:
- The Airbornes;
- The Satellite;
- The Ground Station;
It
follows a list of paper produced by the University of Rome with OPNET
simulation results:
-
P.Dini, G. Ciferri "An Access Protocol
for Multimedia Services Provision in an Avionic Environment"
in Proc. IEEE VTC '04, Milan, Italy
2004
-P.Dini,
M.Massaroni "Admission Control
Policies for WCDMA Satellite Return Link in an Avionic Environment"
in Proc. ESA EMPS/ASMS conference 2004, Noordwijk, The Netherlands,
2004
Report about status of work
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