Area-Power Tradeoffs for Flexible Filtering in Green Radios
Résumé
The energy efficiency of wireless infrastructure and terminals has been drawing renewed attention of late, due to their significant environmental cost. Emerging green communication paradigms like cognitive radio, are also imposing the additional requirements of flexibility. This dual requirements of energy efficiency and flexibility, poses new design challenges for implementing the radio functional blocks. This paper focuses on the area vs. power tradeoffs for the channel filters that are required in the digital frontend of a flexible, energy efficient radio. In traditional CMOS circuits, increased area was traded for reduced dynamic power consumption. With leakage power emerging as the dominant mode of power consumption in nanoscale CMOS, these tradeoffs have to be revisited. The current work discusses how the increased timing slacks obtained by increasing the parallelism, can be exploited for overall power reduction even in nanoscale circuits. In this context a notion of 'area efficiency' and a metric for evaluating it is also introduced. The proposed metric has also been to compare the area efficiencies of different classes of time-shared filters.