  Our motivation in this paper is to take another step forward from complex and
heavyweight synchronization protocols to the easy-to-implement and lightweight
synchronization protocols in WSNs. To this end, we present GraDeS, a novel
multi-hop time synchronization protocol based upon gradient descent algorithm.
We give details about our implementation of GraDeS and present its experimental
evaluation in our testbed of MICAz sensor nodes. Our observations indicate that
GraDeS is scalable, it has identical memory and processing overhead, better
convergence time and comparable synchronization performance as compared to
existing lightweight solutions.
