Abshact-This paper presents EMACs, a medium access protocol especially designed for wireless sensor networks.The medium access protocol consists of a fully distributed and self-organizing TDMA scheme, in which each active node periodidly Listens to the channel and broadcasts a short conhol message. This control message is needed for medium access operation and is also used to piggy bag various types of information at low energy costs.Information in the control message is used to create a maximal independent sef of nodes. This set of nodes creates a mnneeted nehvork and nodes in the set are active, while other nodes are passive and save energy by exploiting the infrastructure created by the connected network.The presented approach is compared in simulation with the SMAC protocol (a medium access protocol with coordinated adaptive sleeping) in B realistic multi-hop network setup where sensor reading are transported to a specific node and mnta are established using the dynamic source routing protocol.The EMACs protocol is able to extend the nehvork lifetime 30% to 55% compared to SMAC in a static network topology and in a dynamic network topolvgy, EMACs prolongs the network lifetime with a factor 2.9 to 4.2.

Abstract. The EYES project (IST-2001-34734) is a three years European research project on self-organizing and collaborative energy-efficient sensor networks. It will address the convergence of distributed information processing, wireless communications, and mobile computing. The goal of the project is to develop the architecture and the technology which enables the creation of a new generation of sensors that can effectively network together so as to provide a flexible platform for the support of a large variety of mobile sensor network applications. This document gives an overview of the EYES project.