Here’s a great talk from Kris Pister Prof. EECS, UC Berkeley, Founder & CTO, Dust Networks. It shows some results from years of experimentation on how to build reliable nets out of nasty unreliable RF channels.
Half of this talk, at CITRIS, is devoted to break down TSMP, a MAC/Network protocol that implements time, space and frequency diversity to provide five 9 reliability communications in a mesh network of sensor nodes.
While some false-starts have limited deployments to date, it seems the dust begins to settle: proven low power solutions for difficult RF environments with multi path interference, thus leading to industry-strength solutions and no site survey installations among different application spaces.
Where are they heading today? Toward a mote on a standard CMOS SoC (~4 mm^2) expected for 2009 and 10 years of battery life out of a coin cell, but then photo-voltaic also potentially embedded in the chip..