International Conference on Sensor Technologies and Applications SENSORCOMM 2007 October 14-20, 2007 - Valencia, Spain

Tutorials

Tutorial 1: Data communication and coordination in wireless sensor and sensor-actuator networks
by Dr Ivan Stojmenovic

Potential audience and interest:

Wireless sensor networks are currently hot topic with rapidly increasing research and commercial interest (new conferences, journals emerged in the area), and data communication and coordination problems are at the center of research activities. The tutorial should attract researchers, graduate and even companies that want to design protocols for real sensor and sensor actuator networks.

Tutorial objective

Wireless sensor and sensor-actuator networks are expected to operate autonomously in unattended environments. They can be remotely connected to the user via one or more base stations (sinks) with direct access to a fixed infrastructure (such as the Internet). Stationary actuators may control sensors by deciding about their activity status (for example, wake up more sensors in areas with anticipated movement or higher reported temperatures) and act upon the environment (for example, by activating its own light/sound alarming or by activating their own water sprinklers). Mobile actuators (which might be co-exist with stationary ones) are robot like devices that can perform additional actions such as (re)placing sensors at needed locations.

While wireless sensor networks attracted enormous research interest, the research of sensor actuator networks is in the initial phases and fundamental network coordination and data communication protocols need to be designed to provide basic functionality to these networks. Examples of problems to be solved are sensor placement by actuators to improve sensing area coverage, minimum energy broadcasting and routing involving actuators, controlled actuator mobility for realization of fault tolerant network, sensor-actuator and actuator-actuator coordination, anycasting (reporting from sensor to the nearest actuator), and actuator movement and coordination to provide accurate localization to sensors.

A tentative outline for the tutorial content is as follows:

Scalable localized routing in wireless sensor networks (route discovery, greedy routing, cost-to-progress ratio framework; power, delay, expected hop count based routing, routing with guaranteed delivery, beaconless routing);

Data communication and gathering in sensor-actuator networks (anycasting, multicasting, LMST based data gathering, location service);

Coordination in sensor and sensor-actuator networks (generating actuator graphs, backbone creation, dominating sets, sensor area coverage, sensor relocation, design guidelines for reporting);
Broadcasting in ad hoc, sensor and actuator networks (clustering, connected dominating sets, neighbor elimination, multi-point relay, beaconless broadcasting, minimum energy broadcasting, parameterless broadcasting from static to mobile networks).

Tutorial will contain new materials not presented in any previous tutorials by the same speaker, such as beaconless routing with guaranteed delivery, LMST based data gathering, parameterless broadcasting, and generating actuator graphs.

The main paradigm shift is to apply localized (or greedy)schemes as opposed to existing protocols requiring global information. Localized algorithms are distributed algorithms where simple local node behaviour achieves a desired global objective. Localized protocols provide scalable solutions, that is, solutions for wireless networks with an arbitrary number of nodes. It is recognized that scalability and functionality for sensor networks operations is only possible with the position information, which becomes available with increasing number of affordable software and hardware solutions. For some other tasks, e.g. broadcasting, position information helps but scalable solutions without it are also possible.

The main objective of the tutorial is to present state of the art research results on data communication and coordination in wireless sensor and sensor-actuator networks, with emphasizes on localized and position based techniques. Physical layer impact on the design of network layer protocols is also discussed. Most of presented techniques are based on localized geometric and graph structures.

Outline of material to be presented (for 3 hours tutorial): transparencies for portion of tutorial on wireless sensor networks are available at www.site.uottawa.ca/~ivan/adhoc.html. Transparencies for wireless sensor-actuator networks will  be added.  Additional slides are available (mostly on the same web site) for longer tutorials.