1. BUCKET: Scheduling of Solar-Powered Sensor Networks via Cross-
Layer Optimization
Abstract:
Renewable solar energy harvesting systems have received considerable
attention as a possible substitute for conventional chemical batteries
in sensor networks. However, it is difficult to optimize the use of solar
energy based only on empirical power acquisition patterns
in sensor networks. We apply acquisition patterns from actual solar energy
harvesting systems and build a framework to maximize the utilization of
solar energy in general sensor networks. Toachieve this goal, we develop a
cross-layer optimization-based scheduling scheme called binding
optimization of duty cycling and networkingthrough energy tracking
(BUCKET), which is formulated in four-stages: 1) prediction of energy
harvesting and arriving traffic; 2) internode optimization at the transport
and network layers; 3) intranode optimization at the medium access
control layer; and 4) flow control of generated communication task sets
using a token-bucket algorithm. Monitoring of the structural health of
bridges is shown to be a potential application of an energy-

2. harvesting sensor network. The example network deploys five sensortypes:
1) temperature; 2) strain gauge; 3) accelerometer; 4) pressure; and 5)
humidity. In the simulations, the BUCKET algorithm displays performance
enhancements of ~12-15% overthose of conventional methods in terms of
the average service rate.