Reinhardt Karnapke

Learn More
Typical sensor nodes are composed of cheap hardware because they have to be affordable in great numbers. This means that memory and communication bandwidth are small, CPUs are slow and energy is limited. It also means that all unnecessary software components must be omitted. Thus it is necessary to use application specific communication protocols. As it is(More)
Radio transceivers for wireless sensor networks are typically cheap devices offering low bandwidth communication only. When physical events in the real world trigger spontaneous communication in many nodes the single communication channel is under heavy load and many messages are lost due to collisions. CSMA/CA schemes are well suited to spontaneous(More)
A lot of applications for wireless sensor networks have been proposed in the last years. Only a few of them have led to real, non-academic deployments, partially due to the differences between end user needs and academic assumptions. In this paper we discuss a real world problem arising from an ecological question (protection of an endangered species) and(More)
Unidirectional links are a common property of all wireless networks. In many cases, the range of these links exceeds that of bidirectional links by far. Still, most protocols ignore their existence or simply discard them. In this paper we introduce two new medium access control (MAC) protocols called MLMAC-UL and ECTS-MAC that are able to transmit data over(More)
—Experiments have shown that unidirectional links are quite common in wireless sensor networks. Still, many MAC protocols ignore their existence, even though they have a tremendous impact on the performance of both TDMA-and contention based protocols. In contention based protocols the medium may be assumed free when it is indeed busy. In TDMA based(More)
Event driven programming is widely used in sensor networks because of the high resource efficiency and the ease of synchronization in such systems. Also, the application logic itself can often be expressed naturally with an event handling system. However, handling of long running tasks is a severe problem, because most systems imply non-preemptive(More)
Communication neighborhood in wireless sensor networks changes often as links break or appear. Therefore, monitoring link quality and (logical) network topology is necessary. As node placement has a large influence on the radio neighborhood and its changes, different positions should be evaluated before starting the actual application. In this paper we(More)