Cross-layer application-specific wireless sensor network design with single-channel CSMA MAC over sense-sleep trees

Because of their pervasiveness and autonomy in operation, mesh-based wireless sensor networks (WSNs) are an ideal candidate in offering sustained monitoring functions at reasonable cost over a wide area. However, devising an energy-efficient, cost-effective, and reliable communication strategy for WSNs requires tight collaboration of all of the sublayers, which introduces new technical challenges in the areas of data, network and power management. This paper proposes a cross-layer sleep scheduling-based organizational approach, called Sense-Sleep Trees (SS-Trees), that aims to harmonize the various engineering issues and provides a method of increasing monitoring coverage and operational lifetime of mesh-based WSNs engaged in wide-area surveillance applications. An iterative algorithmic approach is suggested to determine the feasible SS-Tree structures to achieve such design goals. Based on the computed SS-Trees, optimal sleep schedules and traffic engineering measures can be devised to balance sensing requirements, network communication constraints, and energy efficiency. For channel access, a simple single-channel CSMA MAC with implicit acknowledgements (IACKs) is selected to complement SS-Tree implementation because of its flexibility and adaptability in face of the unique operational characteristics of WSNs.