Energy-Efficient Network Design

Energy management remains a critical problem in ad hoc networks since
battery technology cannot keep up with rising expectations in wireless
communications.  Current approaches to energy conservation focus on
reducing the energy consumption of the wireless interface either for a
given communication task or during idling. However, these
communication-time and idle-time approaches are not necessarily
complementary.  Therefore, we explore the interactions between the two
approaches and their impact on the design of a complete solution to
energy conservation.  Essentially, a complete solution requires
minimizing the energy spent in both communication (i.e., for data and
control overhead) and in idling while satisfying communication needs.
This problem can be expressed as an energy-efficient network design
problem, which is, not surprisingly, NP-hard.  This talk presents our
study of several heuristic approaches to this problem.  Our study
shows that minimizing energy consumed in data transmissions as a
primary goal does not save energy.  Furthermore, jointly reducing
energy consumed for both data and in idling becomes cost-prohibitive
when the energy spent in control overhead is considered.  Hence, we
propose a two-stage approach that prioritizes idling energy
consumption over energy spent for data transmissions.  Due to its low
control overhead, this two-stage approach provides an effective way to
meet the challenge of operating the network with low energy cost.