Design and Implementation of a Power-aware FFT Core for OFDM-based DSA-enabled Cognitive Radios

This research work presents the design and the physical implementation of a power aware FFT core for OFDM-based, dynamic spectrum access (DSA) enabled cognitive radios. The FFT core is equipped with a pruning engine that allows the run-time removal of dummy operations (e.g. multiplications by a zero term) related to the pruning of sub-carriers of the communication systems. The pruning algorithm introduced by this research work utilizes a reduced size configuration matrix, which limits the memory requirements’ overhead. Finally, the physical implementation of the FFT on a 45 nm technology node showed that, for a 8 % area overhead, the total power saving settles around 10 % when in the presence of a medium to high pruning level, justifying the silicon area overhead introduced by the pruning unit.