Hop-by-hop or longer hops: The energy perspective

We investigate, model and compare the expected energy consumption of routing over many short hops to the expected energy consumption of routing over longer hops. In addition to the common energy cost metrics of transmission and reception, our energy cost model also includes idle, noise, multi-path fading and retransmission energy costs. We study and compare various routing scenarios. In all of the scenarios, we consider both the simple disk communication model and the noisy Rayleigh fading channel model. For evaluation purposes, we use the transmission, reception, and idle energy costs along with the noise characteristics of the Mica2 nodes that are widely used in wireless sensor network applications. We perform the comparisons over a range of different system parameters including sleep duration, path-loss exponent and node density and study the trade-offs among the different parameters. We show that under realistic assumptions, for many combinations of the parameters, routing over longer hops is consuming less energy when compared to the shorter-hop routes.