| Summary: | Small wireless devices face resource constraints that demand compromises between
operational range, longevity and data traffic. Reduced device dimensions significantly
impact antenna efficiency and the power capacity of primary cells.
When such a device is implanted under the skin of a young animal, additional
difficulties arise as a result of the losses and detuning effects of the growing tissues. The
species targeted by this research project inhabit an environment characterized by rocky
formations and salt water, further hampering radio frequency communications. Physical
layer design and Medium Access Control (MAC) protocols must work together to
provide adequate performance of the system as a whole.
Herein the Single Channel Sharing Hybrid (SCSH) MAC protocol is developed.
SCSH provides both range and longevity by exploiting the low data transfer requirements
of the application and an environment that allows the use of a Master/Slave star network
topology. After a critical review of several possible designs, the SCSH MAC was
selected as providing the best system performance while achieving the tag longevity goal
of three years, maximizing communications range and minimizing interrogator costs.
The SCSH MAC features scalability to handle an arbitrary number of tags,
exploits low data rates and reporting frequencies to minimize collisions and provides a
mechanism for eliminating redundant transmissions following a collision or otherwise
corrupted transmission. The protocol provides the practical illusion of always-on tag
operation, allowing for on-demand surveys and mitigation of fading effects while
simultaneously ensuring tag longevity goals are met.
The Single Channel Sharing Hybrid with Networked Interrogators (SCSH/NI)
architecture consists of a self-organizing network of small, inexpensive interrogators that
communicate with tags using the SCSH protocol. SCSH/NI interrogators enable coverage
of complex geographies and ensure functionality for short-range communications. === Applied Science, Faculty of === Electrical and Computer Engineering, Department of === Graduate
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