Soutenance de thèse de Fei YIN (LIP6=?iso-8859-1?Q?= 2C_Mardi_20_Janvier_17h00=2C_Salle_550?=)

Bonjour,

It is my pleasure to invite you to attend my oral defense of dissertation
entitled "Performance evaluation and optimization in IEEE 802.16
networks", and the successive party.

Date and Place:
The oral defense will be presented at 17:00 on Tuesday 20th January 2009,
in Room 550 (5th floor) of Laboratoire d'Informatique de Paris 6 (LIP6),
104 avenue du Président Kennedy, 75016 Paris
Access Map: http://www.lip6.fr/fr/informations/comment.php

Members of Jury:
M. Guy PUJOLLE, Professor of Université Pierre et Marie Curie (Advisor)
Mrs. Monique BECKER, Professor of TELECOM SudParis (Reviewer)
M. André-Luc BEYLOT, Professor of ENSEEIHT (Reviewer)
M. Serge FDIDA, Professor of Université Pierre et Marie Curie (Examinator)
M. Ye-Qiong SONG, Professor of INPL (Examinator)
M. Pierre EISENMANN, Chief Operating Officer of N2NSOFT (Examinator)

Abstract:
IEEE 802.16 is a suite of emerging standards that bring the wireless and
broadband access together to fulfil the demand of broadband service
anytime and anywhere. IEEE 802.16 standards suit defines a
reservation-based bandwidth allocation mechanism. In the mechanism, two
main polling modes, the unicast polling mode and the contention-based
polling mode, are defined. The different adoption schemes of the polling
modes result in different configuration of PHY frame structure and then
deeply affect the performance. There should be an optimum scheme to adopt
these two polling modes to optimize the performance. The IEEE 802.16
standards do not specify exactly such a scheme. We investigate the polling
modes in IEEE 802.16 networks, and propose a simple but efficient polling
mechanism to adopt these two polling modes efficiently and fairly and then
optimize the performance.

In IEEE 802.16 networks, the contention-based polling mode is used by the
contention-based and delay-tolerant applications such as nrtPS and BE to
competitively request uplink bandwidth. The amount of bandwidth allocated
for contention-based request will significantly influence the performance.
We analyse and develop a simple mathematical model to evaluate the
performance in IEEE 802.16 networks. An optimal contention-request period
in the frame is presented. This optimal size is also influenced by the
number of terminals in the network, which is also analyzed in the latter.
The simulation results verify that our proposed optimal polling scheme can
allocate bandwidth more efficient and achieve better performance.

Best regards,
Fei YIN