Autour de la réservation de bande passante dans les réseaux ad hoc

Claude Chaudet 1, 2
1 ARES - Architectures of networks of services
Inria Grenoble - Rhône-Alpes, CITI - CITI Centre of Innovation in Telecommunications and Integration of services
Abstract : Wireless networks are a real commercial success nowadays. There is an
increasing number of solutions based on the IEEE 802.11 (Wi-Fi)
standard. Usually, these networks require a base station to transmit
frames between mobiles. Mobile ad hoc networks are mobile, spontaneous
and autonomous wireless networks. Nodes communicate directly without
requiring an intermediate base station. Frames are routed by the network
nodes themselves in the case of a communication between out of range
peers. The sole gathering of wireless-capable terminals is sufficient to
create such a network. This kind of network can be used, for instance,
to extend the range of a wireless network at a very low cost. They can
also be built rapidly, allowing their deployment in emergency
situations.

Radio transmission is somehow particular. The communication range is
limited, the radio medium is pervasive and the mobility of terminals
make the topology evolve rapidly. Usual mechanisms and protocols need to
be adapted to these new constraints, otherwise they will show poor
performance. Numerous works have been contributed in the routing area.
The IETF MANET working group is about to standardize one or several
routing protocols. Nevertheless, open issues such as security, multicast
communication or quality of service still exist. These fields have
gathered much attention during the recent years. Solutions from the
wired world have been examined and adapted but very few really suited
propositions have emerged.

The main topic of this PhD thesis is how to provide efficient bandwidth
reservation in these networks. This work has begun by the design of a
bandwidth reservation protocol taking into account interferences between
emitters that are not able to communicate directly. Indeed, distant
emitters have to share the radio channel bandwidth. These dependencies
should be taken into account and BRuIT, the proposed protocol, brings
this kind of information to the ad hoc nodes in order to enhance the
admission control procedure.

This work has leaded us to the study of the performance of IEEE 802.11
medium access protocol. Existing theoretical studies only concern
one-hop networks in which every node can directly communicate with any
other node. Nevertheless, the presence of distant communications has a
very negative impact on the performance and fairness of this protocol.
We modeled as stochastic processes some pathologic scenarios presenting
fairness issues, this kind of situation being able to impact the free
bandwidth estimation performed by BRuIT.

The medium access protocol being unfair in particular configurations, we
proposed a distributed bandwidth allocation algorithm. This algorithm
intends on indicating to each mobile how much bandwidth it can use
without starving neighbors. The algorithm provides a fair and efficient
allocation, which are often opposite objectives in these networks.

Finally, the last chapter of this manuscript studies hybrid networks
composed of a fixed but wireless architecture providing Internet and
services access to an underlying ad hoc network. We studied the impact
of the control traffic amount on network performance. An optimal
performance requires a compromise between information accuracy and
control traffic volume.

Conceiving a quality of service architecture for these networks is not
an easy task and much remains to be done. Performing an accurate
estimation of the medium capacity provides a great help but this process
has a high cost in terms of overhead. Moreover it seems difficult to
foresee every problematic configuration that can arise in these
networks. Quality of service protocols therefore need to be adaptive in
addition to being as accurate as possible.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00007706
Contributor : Claude Chaudet <>
Submitted on : Sunday, December 19, 2004 - 6:26:53 PM
Last modification on : Saturday, October 27, 2018 - 1:20:10 AM
Long-term archiving on : Friday, April 2, 2010 - 9:04:50 PM

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  • HAL Id : tel-00007706, version 1

Citation

Claude Chaudet. Autour de la réservation de bande passante dans les réseaux ad hoc. Réseaux et télécommunications [cs.NI]. INSA de Lyon, 2004. Français. ⟨tel-00007706⟩

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