  Minimizing the energy consumption of a wireless sensor network application is
crucial for effective realization of the intended application in terms of cost,
lifetime, and functionality. However, the minimizing task is hardly possible as
no overall energy cost function is available for optimization. Optimizing a
specific component of the total energy cost does not help in reducing the total
energy cost as this reduction may be negated by an increase in the energy
consumption of other components of the application. Recently we proposed
Hierarchy Energy Driven Architecture as a robust architecture that takes into
account all principal energy constituents of wireless sensor network
applications. Based on the proposed architecture, this paper presents a single
overall model and proposes a feasible formulation to express the overall energy
consumption of a generic wireless sensor network application in terms of its
energy constituents. The formulation offers a concrete expression for
evaluating the performance of a wireless sensor network application, optimizing
its constituent's operations, and designing more energy-efficient applications.
The paper also presents simulation results to demonstrate the feasibility of
our model and energy formulation
