Wireless Sensor and Actor Networks (WSANs) are distributed systems of heterogeneous
devices, referred to as sensors and actors, which sense, control, and interact with the physical environment.
Sensors are low-cost, low-power, multi-functional devices that communicate untethered
in short distances. Actors are resource-rich devices that collect and process sensor data and consequently
perform actions on the environment.
This thesis is concerned with coordination and communication problems in WSANs, in datacentric
and multimedia application scenarios. First, communication and coordination problems are
jointly addressed in a unifying framework for the case of static actors. A sensor-actor coordination
model is proposed, based on an event-driven partitioning paradigm. Sensors are partitioned into
different sets and each set is associated with a different actor. Data delivery trees are created to
optimally react to the event and timely deliver event data with minimum energy expenditure. The
optimal partitioning strategy is determined bymathematical programming, and a distributed solution
is also proposed. Furthermore, the actor-actor coordination problem is formulated as an optimal task
assignment problem, and a distributed solution of the problem based on an analogy with a one-shot
auction is presented.
Application scenarios for WSANs with mobile actors are then studied. A location management
scheme is introduced to handle the mobility of actors with minimal energy consumption for
resource-constrained sensors. The proposed scheme, which is the first localization scheme specifically
designed for WSANs, is shown to consistently reduce the energy consumption with respect to
existing localization services for ad hoc and sensor networks. An optimal energy-aware forwarding
rule is then derived for sensor-actor communication in fast varying Rayleigh channels. The proposed
scheme allows controlling the delay of the data-delivery process based on power control, and
reacts to network congestion by diverting traffic from congested to lightly-loaded actors. The mobility
of actors is coordinated to optimally accomplish application-specific tasks, based on a nonlinear
optimization model that accounts for location and capabilities of heterogeneous actors.
The research challenges for delivery of multimedia traffic in wireless sensor and actor networks
are then outlined. Finally, a cross-layer communication architecture based on Ultra Wide Band
communications is described, whose design objective is to reliably and flexibly deliver QoS to multimedia
applications in WSANs, by carefully leveraging and controlling interactions among layers
according to application requirements. Performance evaluation shows how the proposed solution
achieves the performance objectives of wireless sensor and actor networks.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/16254 |
| Date | 03 July 2007 |
| Creators | Melodia, Tommaso |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Dissertation |
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