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.

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 multi-failure pattern.