Abstract—Radio frequency (RF) energy harvesting promises
to realize battery-less sensor networks by converting energy
contained in electromagnetic waves into useful electrical energy.
We consider a network architecture that allows heterogeneous
frequency harvesting. One class of sensors harvests RF energy
on the DTV band (614 MHz) while another uses the 915 MHz
ISM band. We study the effective energy transfer that is achieved
under these circumstances, and then design a link layer protocol
called RF-HSN that optimizes the energy delivery to energyhungry
sensors with the optimal duty cycle. To the best of our
knowledge, this is the first wireless energy transfer protocol
for heterogeneous frequency RF energy harvesting, and through
a combination of experimentation and simulation studies, we
demonstrate over 59% higher duty cycle and 66% average
network throughput improvement over the classical CSMA MAC
protocol.
Index Terms—RF harvesting, Optimization, Medium Access
Protocol, Sensor,Wireless power transfer, 915 MHz, DTV.