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.

In this paper we present a novel TDMA-based medium access control (MAC) protocol for wireless sensor networks. Unlike conventional MAC protocols which function independently of the application, we introduce an Adaptive, Informationcentric and Lightweight MAC(AI-LMAC) protocol that adapts its operation depending on the requirements of the application. We also present a completely localised data management framework that helps capture information about traffic patterns in the network. This information is subsequently used by AI-LMAC to modify its operation accordingly. The data management framework can additionally be used for efficient query dissemination and query optimisation. We present preliminary results showing how the MAC protocol efficiently manages the issues of fairness and latency.

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Self organizing, wireless sensors networks are an emergent and challenging technology that is attracting large attention in the sensing and monitoring community. Impressive progress has been done in recent years even if we need to assume that an optimal protocol for every kind of sensor network applications can not exist. As a result it is necessary to optimize the protocol for certain scenarios. In many applications for instance latency is a crucial factor in addition to energy consumption. MERLIN performs its best in such WSNs where there is the need to reduce the latency while ensuring that energy consumption is kept to a minimum. By means of that, the low latency characteristic of MERLIN can be used as a trade of€ to extend node lifetimes. The performance in terms of energy consumption and latency is optimized by acting on the slot length. MERLIN is designed specifically to integrate routing, MAC and localization protocols together. Furthermore it can support data queries which is a typical application for WSNs. The MER-LIN protocol eliminates the necessity to have any explicit handshake mechanism among nodes. Furthermore, the reliability is improved using multiple path message propagation in combination with an overhearing mechanism. The protocol divides the network into subsets where nodes are grouped in time zones. As a result MERLIN also shows a good scalability by utilizing an appropriate scheduling mechanism in combination with a contention period.