Observations on Power-Efficiency Trends in Mobile Communication Devices
1 Department of Electrical and Information Engineering, University of Oulu, P.O. Box 4500, Linnanmaa 90014, Finland
2 Technology Platforms, Nokia Corporation, Elektroniikkatie 3, Oulu 90570, Finland
EURASIP Journal on Embedded Systems 2007, 2007:056976 doi:10.1155/2007/56976Published: 21 March 2007
Computing solutions used in mobile communications equipment are similar to those in personal and mainframe computers. The key differences between the implementations at chip level are the low leakage silicon technology and lower clock frequency used in mobile devices. The hardware and software architectures, including the operating system principles, are strikingly similar, although the mobile computing systems tend to rely more on hardware accelerators. As the performance expectations of mobile devices are increasing towards the personal computer level and beyond, power efficiency is becoming a major bottleneck. So far, the improvements of the silicon processes in mobile phones have been exploited by software designers to increase functionality and to cut development time, while usage times, and energy efficiency, have been kept at levels that satisfy the customers. Here we explain some of the observed developments and consider means of improving energy efficiency. We show that both processor and software architectures have a big impact on power consumption. Properly targeted research is needed to find the means to explicitly optimize system designs for energy efficiency, rather than maximize the nominal throughputs of the processor cores used.