|| For the Spring semester 2005, the schedule of the monthly meetings and invited presentations at OpNeAR
lab. is the following (Please check again for updates):
Friday, January 21, 2005 - 12:00 pm - room ECSN 2.718 |
Cooperative and Non-Cooperative ARQ Protocols for Microwave
Recharged Sensor Nodes
Speaker: Paolo Monti
The Generic Autonomous Platform for Sensor Systems, or GAP4S, is a
maintenance-free wireless sensor network in which the sensor battery
needs not be replaced. Power is delivered to the sensor via a
microwave signal that is radiated by a base-station. The
base-station also acts as the entry point to a wider communication
network, e.g., the Internet.
The presentations will describe three automatic repeat request (ARQ) protocols
that may be used in GAP4S to yield reliable and fair data
transmission from the sensor nodes to the base-station. Two of the
protocols take advantage of cooperative communication, whereby
neighboring sensor nodes help during the retransmission process. The
presented analysis on the saturation throughput of the ARQ protocols
helps quantify the gain achievable when cooperative communication is
used in GAP4S in a variety of working conditions.
|| Friday, February 25, 2005 - 12:00 pm - room ECSN 2.718 |
Local Recovery Solutions from Multi-Link Failures in MPLS-TE Networks
with Probable Failure Patterns
Speaker: Kai Wu
MPLS TE Fast Reroute proposes a local protection mechanism to quickly
reroute protected TE LSPs onto pre-computed and signaled bypass tunnels.
This paper explores the case of multiple network element failure
scenarios. This undesired complexity inherent to the multiple failure
scenario originates from the fact that the latter
failure scenarios are more disruptive, and may require multiple
bypass tunnels to cope with.
The objective of the presentation is to adapt the MPLS local recovery
schemes to multi-failure scenarios, while controlling the
number of bypass tunnels that are required. This objective is
achieved by mapping multi-failure scenarios onto Probable Failure
Patterns (PFP's). PFP's are characterized by their probability (or
frequency) of occurrence during the network lifetime. A number of
bypass tunnels is then computed to effectively cope with the PFP's
according to their frequency or probability of occurrence.
It is shown that by properly choosing how the PFP's are grouped,
and how the corresponding bypass tunnels are computed, it is
possible to trade the required number of bypass tunnels for their
average length and outage probability, i.e., the probability that
the local recovery scheme cannot cope with the occurrence of a
|© 2006. All rights reserved.
Open Networking Advanced Research Lab
Dept. of Electrical Engineering
The University of Texas at Dallas. USA.