  Heat-Diffusion (HD) routing is our recently-developed queue-aware routing
policy for multi-hop wireless networks inspired by Thermodynamics. In the prior
theoretical studies, we have shown that HD routing guarantees throughput
optimality, minimizes a quadratic routing cost, minimizes queue congestion on
the network, and provides a trade-off between routing cost and queueing delay
that is Pareto-Optimal. While striking, these guarantees are based on idealized
assumptions (including global synchronization, centralized control, and
infinite buffers) and heretofore have only been evaluated through simplified
numerical simulations. We present here the first practical decentralized
version of HD algorithm, which we refer to as Heat-Diffusion Collection
Protocol (HDCP), for wireless sensor networks. We present a thorough evaluation
of HDCP based on real testbed experiments, including a comparative analysis of
its performance with respect to the state of the art Collection Tree Protocol
(CTP) and Backpressure Collection Protocol (BCP) for wireless sensor networks.
We find that HDCP has a significantly higher throughput region and greater
resilience to interference compared to CTP. However, we also find that the best
performance of HDCP is comparable to the best performance of BCP, due to the
similarity in their neighbor rankings, which we verify through a Kendall's-Tau
test.
