Power Aware Design of COTS-Based Embedded Internet Systems

An embedded system is a small autonomous computer system that is encapsulated in the device it is controlling. Examples of device with embedded systems are TVs, microwaves, and dishwashers. A modern car can hold as much as 60 microprocessors. Embedded systems sales are rapidly increasing. In fact processor sales for embedded system are much larger than those for personal computers. PC processors only represents 2 percent of all processor sales. The division of EISLAB at Lule̊a University of Technology focuses on research on Embedded internet systems (EIS). Embedded Internet Systems are embedded systems used to collect, process and distribute data over the Internet. EIS devices is a rapidly growing field. The reduced physical size and price of EIS sensors make them attractive to use in a wide range of applications such as; environmental monitoring, industrial, health care, and military surveillance. The vision of EISLAB is sensors with lifetimes in the range of years that will fit within a few cubic centimeters. The sensors developed at EISLAB are based on commercial-ofthe-shelf-components (COTS). Using COTS-components reduces development time and cost for prototypes and small series products. All communication is handled using standardized protocols to give the device access to available communication infrastructure, such as cellular networks and the Internet. As most of the nodes are battery operated the dominant constraint for EIS devices is power consumption. This thesis presents our work to address this topic at a high level of abstraction. The first paper includes the development of a power aware design methodology for EIS devices. In the second paper the proposed design methodology is applied to a bluetooth-equipped device. The third paper discusses the problem of reducing power consumption of an always connected EIS device, showing the tradeoffs between power consumption and response time.