An Area Efficient FFT/IFFT Processor for MIMO-OFDM WLAN 802.11n
A pipelined Fast Fourier Transform and its inverse (FFT/IFFT) processor, which utilizes hardware resources efficiently, is proposed for MIMO-OFDM WLAN 802.11n. Compared with a conventional MIMO-OFDM implementation, (in which as many FFT/IFFT processors as the number of transmit/receive antennas is used), the proposed architecture (using hardware sharing among multiple data sequences) reduces hardware complexity without sacrificing system throughput. Further, the proposed architecture can support 14 input data sequences with sequence lengths of 64 or 128, as needed. The FFT/IFFT processor is synthesized using TSMC 0.18um CMOS technology and saves 25% area compared to a conventional implementation approach using radix-23 algorithm. The proposed FFT/IFFT processor can be configured to improve power efficiency according to the number of input data sequences and the sequence length. The processor consumes 38mW at 75MHz for one input sequence with 64-point length; it consumes 87mW at 75MHz for four input sequences with length 128-point and can be efficiently used for IEEE 802.11n WLAN standard.
mimo-ofdm wlan 802.11n fast fourier transform (fft)