A low-power time-interleaved 128-point FFT for IEEE 802.15.3c standard

This paper proposed a 128-point FFT for low data rate Audio Visual PHY (AVPHY) mode of IEEE 802.15.3c standard. The architecture process a continuous flow of 2 samples in parallel, leading to a throughput of 317.25 MSamples/s with a symbol duration 492 ns. The FFT computed in seven stages that uses radix-2 butterflies and complex rotations. The radix-2 butterflies and complex rotations are time-interleaved by factor of 2. This technique increases the area slightly for the radix-2 butterflies and complex rotators than the conventional radix-2 butterfly and complex rotator. However, this technique reduces the operating frequency of the radix-2 butterflies and complex rotators, which results the reduction of the power consumption of the whole FFT. Besides, the proposed architecture meets requirements of the throughput and latency. Experimental results reveal that besides its requirements, the design is efficient in area and power consumption, improving the results of previous approaches. Specifically, the proposed design consumes 2.87 mW and its area is 0.57 mm2, while the wordlength is 16 bits.