When evaluating MAC layer network protocols for wireless sensor networks performing simulations of a protocol's operation can provide great insight into the performance of the protocol. In order to prove that a protocol will work in a real setting and not just at the theoretical level, however, there is no substitute for evaluation with a physical implementation. This thesis discusses a physical implementation and evaluation of the Many-to-One-Sensor-to-Sink (MOSS) MAC layer protocol for sink based wireless sensor networks using the MAC Layer Architecture for TinyOS. MOSS is a Time Division Multiple Access (TDMA) based protocol first proposed in an earlier work. MOSS aims to utilize the strengths and alleviate the weaknesses of TDMA. In addition to discussing and evaluating the physical MOSS implementation, the process of developing MAC layer protocol implementations with MLA is also discussed.

[Truncated abstract] This thesis develops a scheduled protocol (time division multiple access, TDMA) called flexible-schedule-based TDMA Protocol (FlexiTP), to address the problem of providing end-to-end guarantees on data delivery, whilst also respecting severe resource constraints of wireless sensor networks. FlexiTP achieves this balance through a distributed, synchronised, and loose slot structure in which sensor nodes can build, modify, or extend their schedules based on their local information. In FlexiTP, it is not necessary to predetermine the number of slots required for a network. FlexiTP's local repair scheme allows nodes to adjust their schedules dynamically and autonomously to recover from node and communication faults. Hence, it maintains a reliable and selforganising multihop network. Most sensor network protocols designed for data gathering applications implicitly assume a periodic rate of data collection from all nodes in the network to the base station. However, nodes may want to report their data more rapidly or slowly depending on the significance and importance of their data to the end-user. The problem is that traditional TDMA-based protocols are not flexible to changes in traffic patterns because of their rigid slot structure schemes. This thesis aims to solve this problem by developing an ondemand TDMA slot transfer method that leverages the flexible-slot structure algorithm of FlexiTP to transfer time slots from one part of the network to another part. ... While these communication patterns are sufficient for monitoring applications, individual sensor nodes may need to send their data to multiple destination nodes across the network in order to execute a distributed cooperative-function based on their local environment. This peer-to-peer communication pattern makes sensor networks more reactive to triggers from the environment. This thesis attempts to solve the problem of lack of peer-to-peer communication in the design of a TDMA-driven protocol by extending the idea of on-demand TDMA slot transfer method to allow each sensor node in the network to claim extra time slots to communicate with any other nodes (peers) in the network, without going through the base station. Nodes in the network may have different priorities of data because of event-triggering sensor readings or various types of sensor readings (e.g., light, temperature, and humidity) they provide. When nodes with high priority packets increase the frequency of their data collections, the network bandwidth may be dominated by these nodes. It is desirable to allow nodes with low priority packets to aggregate their packets and so enabling these nodes to send their data to the base station under the current available network bandwidth. This thesis proposes an on-demand data aggregation algorithm that enables sensor nodes to perform an in-network-aggregation based on their current sensing requirements and network capacity constraints. In summary, this thesis describes the design, implementation, and evaluation of protocols for wireless sensor networks that focus on achieving energy-efficiency, provisioning performance assurances, and supporting reactivity and adaptability in constantly changing environment.

[Truncated abstract] Developing wireless sensor network communication protocols for industrial environments is a challenging task. The wireless channel conditions in industrial environments are harsher as a result of multipath propagation of radio signals within an environment where the mechanics of the surrounding industrial activities often lead to severe small-scale fading effects. The design of network protocols to function in such an environment needs to provide a robust communication platform for the wireless sensor nodes, while optimizing the utilization of the limited node resources available. As existing general MAC protocols for wireless sensor networks do not work well under harsh channel conditions, we address this problem in this thesis by proposing a medium access control (MAC) protocol framework for wireless sensor networks in industrial environments. To describe the impact of an automated industrial site on small-scale fading effects in an industrial indoor wireless network, we use a site-specific ray-tracer for predicting signal propagation based on building blue prints to simulate the signal propagation paths through an industrial site with periodically moving objects. We found that in a fully automated industrial site, the periodic movements of objects with constant velocities result in an approximately periodic distribution of fading periods in the channel. Based on this finding, we propose a link state dependent TDMA-based MAC protocol for wireless sensor networks designed for automated industrial applications. ... This technique also conserves energy and maximizes packet integrity as the sensor nodes avoid performing network activities when the channel is sampled to be affected by fading. As a measure for fault-tolerance, we also propose a dynamic link reconstruction technique that allows sensor nodes to reconstruct new parent links when their present links are severely affected by fading. MAC protocols that adopt active buffering in fading-affected channels suffer bufferoverflow and latency issues as a result of the postponement of scheduled transmissions during periods when the channel is in a fade. Consequently, time-sensitive data packets that may contain critical information may miss their deadlines in a severely affected fading channel. Hence, we propose a general fading-aware data management (FADE) MAC protocol extension that uses buffer nodes to offload the memory buffer off sensor nodes in the network and prioritizes traffic based on a simple proposed priority scheme. The FADE extension provides a balance balance between minimum end-to-end latency for critical event reporting, high packet delivery guarantee, low energy consumption, and minimum buffer requirements on the sensor nodes. In summary, this thesis presents the design, implementation, and evaluation of all our proposed network protocols that are combined as a framework for wireless sensor networks in industrial environments.

Wireless sensor networks are deployed in a rapidly increasing number of arenas, with uses ranging from healthcare monitoring to industrial and environmental safety, as well as new ubiquitous computing devices that are becoming ever more pervasive in our interconnected society. This book presents a range of exciting developments in software communication technologies including some novel applications, such as in high altitude systems, ground heat exchangers and body sensor networks. Authors from leading institutions on four continents present their latest findings in the spirit of exchanging information and stimulating discussion in the WSN community worldwide.

This book constitutes the refereed proceedings of the 8th European Conference on Wireless Sensor Networks, EWSN 2011, held in Bonn, Germany, in February 2011. The 14 revised full papers presented were carefully reviewed and selected from 87 submissions. The papers are organized in topical sections on routing and mobility, optimization techniques, MAC protocols, algorithms, and systems and abstractions.

This book constitutes the refereed proceedings of the 15th International GI/ITG Conference on "Measurement, Modelling and Evaluation of Computing Systems" and "Dependability and Fault Tolerance", held in Essen, Germany, in March 2010. The 19 revised full papers presented together with 5 tool papers and 2 invited lectures were carefully reviewed and selected from 42 initial submissions. The papers cover all aspects of performance and dependability evaluation of systems including networks, computer architectures, distributed systems, software, fault-tolerant and secure systems.

"This book focuses on wireless sensor networks and their operation, covering topics including routing, energy efficiency and management"--